P–732 Maternal over-the-counter analgesics use during pregnancy and adverse perinatal outcomes: cohort study of 151,141 singleton pregnancies

Study question

Is in utero exposure to five over-the-counter (non-prescription) analgesics (paracetamol, ibuprofen, aspirin, diclofenac, naproxen) associated with offspring health outcomes?

Summary answer

Consumption of over-the-counter analgesics during pregnancy, either as single compounds or in combinations, is significantly associated with a variety of adverse offspring health outcomes.

What is known already

A high percentage of pregnant women use over-the-counter analgesics during pregnancy globally. Some of these compounds such as paracetamol are considered safe to use, while contraindications exist for others, such as NSAIDs use beyond gestational week 30. Current evidence regarding the safety of use during pregnancy in humans is largely conflicting. Results from many published human studies on the topic suffer from limitations including use of small cohorts, short study time or failure to adjust for important confounders. These may explain conflicting results that cause significant concern regarding evidence-based prenatal guidance on use during pregnancy.

Study design, size, duration

Retrospective cohort study using the Aberdeen Maternity and Neonatal Databank. Data from 151,141 singleton pregnancies over 30 years (between 1985 and 2015) were used. Consumption of paracetamol, ibuprofen, aspirin, diclofenac and naproxen during pregnancy was recorded in medical notes of each woman. In our analysis, the control group was pregnancies where no analgesic was consumed, and the exposure groups included pregnancies with over-the-counter analgesic consumption either in combinations or as single compound use.

Participants/materials, setting, methods

Maternal baseline characteristics were compared using χ2 tests for categorical variables and Mann-Whitney for continuous variables (significance at < 0.05). Premature delivery, stillbirth, neonatal death, baby weight, neonatal unit admission, APGAR score at 1 and 5 minutes, neural tube defects, amniotic band defects, gastroschisis, and, in males only, hypospadias and cryptorchidism, were the outcomes assessed. Crude (cORs) and adjusted odds ratios (aORs) with 95% confidence intervals (CIs) were calculated using logistic regression to control for confounders.

Main results and the role of chance

The overall prevalence of over-the-counter analgesics use during pregnancy was 29.1%, increasing over the 30-year study period, to over 60% of women in the last seven years of the study. 83.7% of those women reported first trimester use when specifically asked at their first antenatal clinic visit. Pregnancies exposed to at least one of the five analgesics were independently associated with increased risks for premature delivery <37 weeks (aOR=1.50, 95%CI 1.43–1.58), stillbirth (aOR=1.33, 95%CI 1.15–1.54), neonatal death (aOR=1.56, 95%CI 1.27–1.93), birthweight <2,500g (aOR=1.28, 95%CI 1.20–1.37), birthweight >4,000g (aOR=1.09, 95%CI 1.05–1.13), admission to neonatal unit (aOR=1.57, 95%CI 1.51–1.64), APGAR score <7 at 1 minute (aOR=1.18, 95%CI 1.13–1.23) and 5 minutes (aOR=1.48, 95%CI 1.35–1.62), neural tube defects (aOR=1.64, 95%CI 1.08–2.47) and hypospadias (aOR=1.27, 95%CI 1.05–1.54 males only). ). Associations of paracetamol alone with high birth weight, neural tube defects and hypospadias were not significant in the adjusted analysis. Diclofenac consumption was associated with significantly decreased odds of stillbirth (aOR=0.59, 95%CI 0.41–0.87).

Limitations, reasons for caution

Our data were based on medical notes; however, consumption is self-reported, and details on the timing, dosage, product type (single-ingredient vs combination) and administration type were not available in the database. Our study only considered neonatal health outcomes and longer-term follow-up of the offspring was not available at this time.

Wider implications of the findings: This is one of the largest and most comprehensive studies into analgesic use in pregnancy. The increased risks of adverse neonatal outcomes associated with non-prescribed, over-the-counter, analgesics use during pregnancy indicate that healthcare guidance for pregnant women regarding analgesic use should be re-assessed.

Trial registration number

N/A

Genome-wide expression changes induced by bisphenol A, F and S in human stem cell derived hepatocyte-like cells

The debate about possible adverse effects of bisphenol A (BPA) has been ongoing for decades. Bisphenol F (BPF) and S (BPS) have been suggested as “safer” alternatives. In the present study we used hepatocyte-like cells (HLCs) derived from the human embryonic stem cell lines Man12 and H9 to compare the three bisphenol derivatives. Stem cell-derived progenitors were produced using an established system and were exposed to BPA, BPF and BPS for 8 days during their transition to HLCs. Subsequently, we examined cell viability, inhibition of cytochrome P450 (CYP) activity, and genome-wide RNA profiles. Sub-cytotoxic, inhibitory concentrations (IC₅₀) of CYP3A were 20, 9.5 and 25 µM for BPA, BPF and BPS in Man12 derived HLCs, respectively. The corresponding concentrations for H9-derived HLCs were 19, 29 and 31 µM. These IC₅₀ concentrations were used to study global expression changes in this in vitro study and are higher than unconjugated BPA in serum of the general population. A large overlap of up- as well as downregulated genes induced by the three bisphenol derivatives was seen. This is at least 28-fold higher compared to randomly expected gene expression changes. Moreover, highly significant correlations of expression changes induced by the three bisphenol derivatives were obtained in pairwise comparisons. Dysregulated genes were associated with reduced metabolic function, cellular differentiation, embryonic development, cell survival and apoptosis. In conclusion, no major differences in cytochrome inhibitory activities of BPA, BPF and BPS were observed and gene expression changes showed a high degree of similarity.

Identification of Sertoli cell-specific transcripts in the mouse testis and the role of FSH and androgen in the control of Sertoli cell activity

Background

The Sertoli cells act to induce testis differentiation and subsequent development in fetal and post-natal life which makes them key to an understanding of testis biology. As a major step towards characterisation of factors involved in Sertoli cell function we have identified Sertoli cell-specific transcripts in the mouse testis and have used the data to identify Sertoli cell-specific transcripts altered in mice lacking follicle-stimulating hormone receptors (FSHRKO) and/or androgen receptors (AR) in the Sertoli cells (SCARKO).

Results

Adult iDTR mice were injected with busulfan to ablate the germ cells and 50 days later they were treated with diphtheria toxin (DTX) to ablate the Sertoli cells. RNAseq carried out on testes from control, busulfan-treated and busulfan + DTX-treated mice identified 701 Sertoli-specific transcripts and 4302 germ cell-specific transcripts. This data was mapped against results from microarrays using testicular mRNA from 20 day-old FSHRKO, SCARKO and FSHRKO.SCARKO mice. Results show that of the 534 Sertoli cell-specific transcripts present on the gene chips, 85% were altered in the FSHRKO mice and 94% in the SCARKO mice (mostly reduced in both cases). In the FSHRKO.SCARKO mice additive or synergistic effects were seen for most transcripts. Age-dependent studies on a selected number of Sertoli cell-specific transcripts, showed that the marked effects in the FSHRKO at 20 days had largely disappeared by adulthood although synergistic effects of FSHR and AR knockout were seen.

Conclusions

These studies have identified the Sertoli cell-specific transcriptome in the mouse testis and have shown that most genes in the transcriptome are FSH- and androgen-dependent at puberty although the importance of FSH diminishes towards adulthood.

Electronic supplementary material

The online version of this article (10.1186/s12864-017-4357-3) contains supplementary material, which is available to authorized users.

Daily and seasonal cycles of body temperature and aspects of heterothermy in the hedgehog Eriuaceus europaeus

Summary. Intra-abdominal temperature-sensitive radio transmitters were used to collect more than 350 sets of body temperature (Tb) data from 23 captive adult hedgehogs over a 3-year period. Each data set comprised measurements made every 1/2 h for 24-h periods. Between 20 and 60 such data sets were recorded every calendar month, and a total of 17400 measurements of Tb were collected. The hedgehogs were exposed to natural environmental conditions at 57 ⁰N in NE Scotlad. Hedgehogs showed seasonal changes in mean daily euthermic Tb, with a July maximum of 35.9±0.2 ⁰C a September minimum of 34.7± 0.9 ⁰C and a marked circadian Tb cycle that correlates closely with photoperiod Maximal Tb occurred within 2 h of midnight and this pattern of nocturnal maximum and diurnal minimum Tb was most marked between April and September. The circadian Tbcycle was least correlated with photoperiod during winter. Hibernal Tb during winter correlated with ambient temperature (Ta), it was maximal in September(17.7± 1.0 ⁰C and minimal in December (5.2±0.9 ⁰C Apart from the tracking of Ta and Tb during hibernalb outs, with a time-lag of 4-6 h, circadian rhythmicity of hibernal Tb was not evident. However, the Tb of hibernating hedgehogs rose significantly when Ta fell below-5 ⁰C although the animals did not neccessarily arouse.Although hibernal bouts occurred between September and April, 89.5% of such bouts were recorded between November and February. The mean time of entry into hibernation was 01:45 ±5./h GMT while the mean time of the start of spontaneous arousal from hibernation was 11 : 53 ± 4.8 h GMT. Therefore, during hibernation hedgehogs were either fully aroused at night,when euthermic hedgehogs have maximal Tb, or in deep hibernation around midday, when euthermic hedgehogs have minimal Tb. Since wild hedgehogs will feed during spontaneous arousal from hibernation, these timings are probably adaptive, and suggest that entry into, and arousal from, hibernation may be extensions of circadian cyclicity. Spontaneous bouts of transient shallow torpor (TST) were recorded throughout the year, with nearly 80% of observations occurring during August and September, at the start of the hibernal period. TST bouts lasted for 4.9±2.9 h, with T b falling to 25.8±3.1 ⁰C Only 20% of TST bouts immediately preceded hibernation and their duration did not correlate with Ta or body mass. TST bouts started at O6:51± 4.7 h GMT, significantly later than entry into hibernation, and ended at 13:04±5.4 h GMT. The function of TST bouts is unclear,but they may be preparation for the hibernation season or a further energy conservation strategy. When arousing from hibernation hedgehogs warmed at a rate of 1.9±0.4⁰C -1, and when entering hibernation cooled at 7.9±1.9 ⁰C h- 1. Warming rates were slightly higher during mid-winter when Tb and body mass were minimal, but cooling rates were 44% higher at the end of the hibernal period compared to the start. Cooling and warming rates were strikingly similar to those measured in hedgehogs at 31 ⁰N These results demonstrate that thermoregulation in the hedgehog is closely regulated and changes on a seasonal basis, in meeting with requirements of surviving food shortages and low temperature during winter.

Timing of Maternal Exposure and Foetal Sex Determine the Effects of Low-level Chemical Mixture Exposure on the Foetal Neuroendocrine System in Sheep

We have shown that continuous maternal exposure to the complex mixture of environmental chemicals (ECs) found in human biosolids (sewage sludge), disrupts mRNA expression of genes crucial for development and long-term regulation of hypothalamic-pituitary gonadal (HPG) function in sheep. The present study investigated whether exposure to ECs only during preconceptional period or only during pregnancy perturbed key regulatory genes within the hypothalamus and pituitary gland and whether these effects were different from chronic (life-long) exposure to biosolid ECs. The findings demonstrate that the timing and duration of maternal EC exposure influences the subsequent effects on the foetal neuroendocrine system in a sex-specific manner. Maternal exposure prior to conception, or during pregnancy only, altered the expression of key foetal neuroendocrine regulatory systems such as gonadotrophin-releasing hormone and kisspeptin to a greater extent than when maternal exposure was 'life-long'. Furthermore, hypothalamic gene expression was affected to a greater extent in males than in females and, following EC exposure, male foetuses expressed more 'female-like' mRNA levels for some key neuroendocrine genes. This is the first study to show that 'real-life' maternal exposure to low levels of a complex cocktail of chemicals prior to conception can subsequently affect the developing foetal neuroendocrine system. These findings demonstrate that the developing neuroendocrine system is sensitive to EC mixtures in a sex-dimorphic manner likely to predispose to reproductive dysfunction in later life.

Reproduction Symposium: does grazing on biosolids-treated pasture pose a pathophysiological risk associated with increased exposure to endocrine disrupting compounds?

Biosolids (processed human sewage sludge), which contain low individual concentrations of an array of contaminants including heavy metals and organic pollutants such as polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyls (PCB), and polychlorinated dibenzodioxins/polychlorinated dibenzofurans known to cause physiological disturbances, are increasingly being used as an agricultural fertilizer. This could pose a health threat to both humans and domestic and wild animal species. This review summarizes results of a unique model, used to determine the effects of exposure to mixtures of environmentally relevant concentrations of pollutants, in sheep grazed on biosolids-treated pastures. Pasture treatment results in nonsignificant increases in environmental chemical (EC) concentrations in soil. Whereas EC concentrations were increased in some tissues of both ewes and their fetuses, concentrations were low and variable and deemed to pose little risk to consumer health. Investigation of the effects of gestational EC exposure on fetal development has highlighted a number of issues. The results indicate that gestational EC exposure can adversely affect gonadal development (males and females) and that these effects can impact testicular morphology, ovarian follicle numbers and health, and the transcriptome and proteome in adult animals. In addition, EC exposure can be associated with altered expression of GnRH, GnRH receptors, galanin receptors, and kisspeptin mRNA within the hypothalamus and pituitary gland, gonadotroph populations within the pituitary gland, and regional aberrations in thyroid morphology. In most cases, these anatomical and functional differences do not result in altered peripheral hormone concentrations or reproductive function (e.g., lambing rate), indicating physiological compensation under the conditions tested. Physiological compensation is also suggested from studies that indicate that EC effects may be greater when exposure occurs either before or during gestation compared with EC exposure throughout life. With regard to human and animal health, this body of work questions the concept of safe individual concentration of EC when EC exposure typically occurs as complex mixtures. It suggests that developmental EC exposure may affect many different physiological systems, with some sex-specific differences in EC sensitivity, and that EC effects may be masked under favorable physiological conditions.

Proteomic analysis of the sheep caruncular and intercaruncular endometrium reveals changes in functional proteins crucial for the establishment of pregnancy

The expression and regulation of endometrial proteins are crucial for conceptus implantation and development. However, little is known about site-specific proteome profiles of the mammalian endometrium during the peri-implantation period. We utilised a two-dimensional gel electrophoresis/mass spectrometry-based proteomics approach to compare and identify differentially expressed proteins in sheep endometrium. Caruncular and intercaruncular endometrium were collected on days 12 (C12) and 16 (C16) of the oestrous cycle and at three stages of pregnancy corresponding to conceptus pre-attachment (P12), implantation (P16) and post-implantation (P20). Abundance and localisation changes in differentially expressed proteins were determined by western blot and immunohistochemistry. In caruncular endometrium, 45 protein spots (5% of total spots) altered between day 12 of pregnancy (P12) and P16 while 85 protein spots (10% of total spots) were differentially expressed between P16 and C16. In intercaruncular endometrium, 31 protein spots (2% of total spots) were different between P12 and P16 while 44 protein spots (4% of total spots) showed differential expression between C12 and C16. The pattern of protein changes between caruncle and intercaruncle sites was markedly different. Among the protein spots with implantation-related changes in volume, 11 proteins in the caruncular endometrium and six proteins in the intercaruncular endometrium, with different functions such as protein synthesis and degradation, antioxidant defence, cell structural integrity, adhesion and signal transduction, were identified. Our findings highlight the different but important roles of the caruncular and intercaruncular proteins during early pregnancy.

Identification of Leydig cell-specific mRNA transcripts in the adult rat testis

The adult population of Leydig cells acts to secrete testosterone which is essential for reproductive health and fertility in the adult male. However, other physiological functions of these cells are uncertain, and to address this issue a cell ablation model has been used to identify Leydig cell-specific mRNA transcripts. Ethane dimethane sulphonate (EDS) was synthesised by a novel process and was used to ablate Leydig cells in adult male rats previously treated with butane dimethane sulphonate (busulphan) to delete the germ cell population. Levels of mRNA transcripts were measured in the testis using microarrays 1, 3, 5, 8 and 12 days after EDS injection. During this period, there was a significant change in the levels of 2200 different transcripts with a marked decline in the levels of canonical Leydig cell transcripts, such as Cyp11a1, Cyp17a1 and Insl3. A total of 95 transcripts showed a similar decline in expression after EDS treatment, suggesting that they have a Leydig cell-specific origin. Analysis of selected transcripts confirmed that they were expressed specifically in Leydig cells and showed that most had a late onset of expression during adult Leydig cell development. Apart from transcripts encoding components of the steroidogenic apparatus, the most common predicted function of translated proteins was endogenous and xenotoxicant metabolism. In addition, a number of transcripts encode acute-phase proteins involved in reduction of oxidative stress. Results show that, in addition to androgen secretion, Leydig cells may have a critical role to play in protecting the testis from damage caused by toxicants or stress.

Steroidogenic enzyme expression in the human fetal liver and potential role in the endocrinology of pregnancy

The human feto-maternal unit produces large amounts of steroid hormones, particularly estrogens, during the second and third trimesters. The fetal adrenal gland and the placenta are considered the principal tissues driving steroid production but the fetal liver is likely to play an essential role in this process. This study was designed to measure transcript expression of proteins involved in steroid synthesis, metabolism, conjugation and signalling in the human fetal liver and to examine sex differences and effects of maternal smoking. Liver samples were taken from 55 normal fetuses from women undergoing second trimester elective termination. Levels of 23 mRNA transcripts encoding steroid synthesis/metabolic/conjugation enzymes and steroid receptors were measured by real-time PCR. The expression of representative proteins was confirmed by western blotting and immunohistochemistry. The human fetal livers expressed high levels of CYP19A1, SULT2A1, SULT1E1, HSD17B2, SRD5A3 and CYP3A7. Lower levels of SULT1A1, STS, UGT2B17, GPER, AKR1C3, UGT2B15, AR, CYP11A1, CYP21A2, HSD17B3, HSD17B1 and SRD5A1 were also detectable. The expression of ESR, ESR2, CYP17A1 and HSD3B transcripts was undetectable in most fetal livers, although HSD3B was shown to be present by western blotting. Sex differences were limited to SRD5A3 (lower in females) and UGT2B17 (higher in females). Maternal smoking increased the expression of CYP19A1, SULT2A1, UGT2B17, HSD17B2 and AKR1C3 and reduced the expression of SRD5A3 in the male fetal liver. This study shows that the human fetal liver is likely to have an extensive effect on circulating steroid levels in the human fetus and mother. The most important of these effects will be alterations to the species, conjugation and availability of estrogens in the fetus. Maternal smoking is likely to reduce circulating androgen bioactivity in male fetuses.

Foetal and post-natal exposure of sheep to sewage sludge chemicals disrupts sperm production in adulthood in a subset of animals

Exposure to ubiquitous, environmental chemicals (ECs) has been hypothesized as a cause for declining male reproductive health. Understanding the long-term effects of EC exposure on reproductive health in humans requires animal models and exposure to ‘real life’, environmentally relevant, mixtures during development, a life stage of particular sensitivity to ECs. The aim of this study was to evaluate the effects of in utero and post-natal exposure to environmentally relevant levels of ECs, via sewage sludge application to pasture, on the adult male sheep testis. Hormones, liver concentrations of candidate ECs and Sertoli and germ cell numbers in testes of adult rams that were exposed to ECs in sewage sludge in utero, and until weaning via maternal exposure, and post-weaning via grazing pastures fertilized with sewage sludge, were quantified. Evaluated as a single group, exposure to sludge ECs was without significant effect on most parameters. However, a more detailed study revealed that 5 of 12 sludge-exposed rams exhibited major spermatogenic abnormalities. These consisted of major reductions in germ cell numbers per testis or per Sertoli cell and more Sertoli cell-only tubules, when compared with controls, which did not show any such changes. The sludge-related spermatogenic changes in the five affected animals were significantly different from controls (p < 0.001); Sertoli cell number was unaffected. Hormone profiles and liver candidate EC concentrations were not measurably affected by exposure. We conclude that developmental exposure of male sheep to real-world mixtures of ECs can result in major reduction in germ cell numbers, indicative of impaired sperm production, in a proportion of exposed males. The individual-specific effects are presumed to reflect EC effects on a heterogeneous population in which some individuals may be more susceptible to adverse EC effects. Such effects of EC exposure in humans could have adverse consequences for sperm counts and fertility in some exposed males.

Maternal and fetal tissue accumulation of selected endocrine disrupting compounds (EDCs) following exposure to sewage sludge-treated pastures before or after conception

Liver concentrations of selected pollutant classes were determined in groups of sheep fetuses and their dams, at 55 (Experiment 1) and 110 (Experiment 2) days of gestation (term = 145 d) following exposure, throughout their breeding lives and after mating, to pasture treated with either inorganic fertiliser (control, CC) or with sewage sludge (treated, TT). In a unique study designed to separate the respective contributions of environmental sources and mobilised tissue to the available EDC burden, in additional groups of animals, pollutant burdens at 110 days gestation were assessed following exposure to the respective treatments, either throughout their breeding lives until mating, but not thereafter (TC), or only between mating and slaughter (CT) (Experiment 3). With very few exceptions, maternal and fetal liver concentrations of diethylhexyl phthalate (DEHP) and selected polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDE) and polycyclic aromatic hydrocarbons (PAHs) were not significantly affected by sludge exposure in any group. In some cases, maternal and fetal tissue EDC concentrations were different but the differences were not consistent, and maternal and fetal concentrations of none of the classes of chemical were significantly correlated. It was not possible to identify a single chemical, or class of chemical, that may be responsible for previously observed physiological effects of exposure to sludge-treated pastures. It is concluded that exposure of sheep to pastures fertilised with sewage sludge was not associated with increased liver concentrations of EDCs, irrespective of the stage of development at which they were measured and of maternal tissue mobilisation and EDC release during gestation. Thus, retrospective measurements of EDC tissue burdens could not be used to accurately assess earlier fetal EDC insults.

Effects of environmental pollutants on the reproduction and welfare of ruminants

Anthropogenic pollutants comprise a wide range of synthetic organic compounds and heavy metals, which are dispersed throughout the environment, usually at low concentrations. Exposure of ruminants, as for all other animals, is unavoidable and while the levels of exposure to most chemicals are usually too low to induce any physiological effects, combinations of pollutants can act additively or synergistically to perturb multiple physiological systems at all ages but particularly in the developing foetus. In sheep, organs affected by pollutant exposure include the ovary, testis, hypothalamus and pituitary gland and bone. Reported effects of exposure include changes in organ weight and gross structure, histology and gene and protein expression but these changes are not reflected in changes in reproductive performance under the conditions tested. These results illustrate the complexity of the effects of endocrine disrupting compounds on the reproductive axis, which make it difficult to extrapolate between, or even within, species. Effects of pollutant exposure on the thyroid gland, immune, cardiovascular and obesogenic systems have not been shown explicitly, in ruminants, but work on other species suggests that these systems can also be perturbed. It is concluded that exposure to a mixture of anthropogenic pollutants has significant effects on a wide variety of physiological systems, including the reproductive system. Although this physiological insult has not yet been shown to lead to a reduction in ruminant gross performance, there are already reports indicating that anthropogenic pollutant exposure can compromise several physiological systems and may pose a significant threat to both reproductive performance and welfare in the longer term. At present, many potential mechanisms of action for individual chemicals have been identified but knowledge of factors affecting the rate of tissue exposure and of the effects of combinations of chemicals on physiological systems is poor. Nevertheless, both are vital for the identification of risks to animal productivity and welfare.

Foetal hypothalamic and pituitary expression of gonadotrophin-releasing hormone and galanin systems is disturbed by exposure to sewage sludge chemicals via maternal ingestion

Animals and humans are chronically exposed to endocrine disrupting chemicals (EDCs) that are ubiquitous in the environment. There are strong circumstantial links between environmental EDC exposure and both declining human/wildlife reproductive health and the increasing incidence of reproductive system abnormalities. The verification of such links, however, is difficult and requires animal models exposed to 'real life', environmentally relevant concentrations/mixtures of environmental contaminants (ECs), particularly in utero, when sensitivity to EC exposure is high. The present study aimed to determine whether the foetal sheep reproductive neuroendocrine axis, particularly gondotrophin-releasing hormone (GnRH) and galaninergic systems, were affected by maternal exposure to a complex mixture of chemicals, applied to pasture, in the form of sewage sludge. Sewage sludge contains high concentrations of a spectrum of EDCs and other pollutants, relative to environmental concentrations, but is frequently recycled to land as a fertiliser. We found that foetuses exposed to the EDC mixture in utero through their mothers had lower GnRH mRNA expression in the hypothalamus and lower GnRH receptor (GnRHR) and galanin receptor (GALR) mRNA expression in the hypothalamus and pituitary gland. Strikingly, this, treatment had no significant effect on maternal GnRH or GnRHR mRNA expression, although GALR mRNA expression within the maternal hypothalamus and pituitary gland was reduced. The present study clearly demonstrates that the developing foetal neuroendocrine axis is sensitive to real-world mixtures of environmental chemicals. Given the important role of GnRH and GnRHR in the regulation of reproductive function, its known role programming role in utero, and the role of galanin in the regulation of many physiological/neuroendocrine systems, in utero changes in the activity of these systems are likely to have long-term consequences in adulthood and represent a novel pathway through which EC mixtures could perturb normal reproductive function.

Developmental changes in human fetal testicular cell numbers and messenger ribonucleic acid levels during the second trimester

CONTEXT

Normal fetal testis development is essential for masculinization and subsequent adult fertility. The second trimester is a critical period of human testicular development and masculinization, but there is a paucity of reliable developmental data.

OBJECTIVE

The objective of the study was to analyze second-trimester human testicular morphology and function.

DESIGN

This was an observational study of second-trimester testis development.

SETTING

The study was conducted at the Universities of Glasgow and Aberdeen.

PATIENTS/PARTICIPANTS

Testes were collected from 57 morphologically normal fetuses of women undergoing elective termination of normally progressing pregnancies (11-19 wk gestation).

MAIN OUTCOME MEASURE(S)

Testicular morphology, cell numbers, and quantitative expression of 22 key testicular genes were determined.

RESULTS

Sertoli cell and germ cell number increased exponentially throughout the second trimester. Leydig cell number initially increased exponentially but slowed toward 19 wk. Transcripts encoding Sertoli (KITL, FGF9, SOX9, FSHR, WT1) and germ (CKIT, TFAP2C) cell-specific products increased per testis through the second trimester, but expression per cell was static apart from TFAP2C, which declined. Leydig cell transcripts (HSD17B3, CYP11A1, PTC1, CYP17, LHR, INSL3) also remained static per cell. Testicular expression of adrenal transcripts MC2R, CYP11B1, and CYP21 was detectable but unchanged. Expression of other transcripts known or postulated to be involved in testicular development (GATA4, GATA6, CXORF6, WNT2B, WNT4, WNT5A) increased significantly per testis during the second trimester.

CONCLUSIONS

The second trimester is essential for the establishment of Sertoli and germ cell numbers. Sertoli and Leydig cells are active throughout the period, but there is no evidence of changing transcript levels.

Regulation of functional steroid receptors and ligand-induced responses in telomerase-immortalized human endometrial epithelial cells

Information on the regulation of steroid hormone receptors and their distinct functions within the human endometrial epithelium is largely unavailable. We have immortalized human primary endometrial epithelial cells (EECs) isolated from a normal proliferative phase endometrium by stably transfecting the catalytic subunit (hTERT) of the human telomerase complex and cultured these hTERT-EECs now for over 350 population doublings. Active hTERT was detected in hTERT-EECs employing the telomerase repeat amplification assay protocol. hTERT-EECs revealed a polarized, non-invasive epithelial phenotype with apical microvilli and production of a basal lamina when grown on a three-dimensional collagen-fibroblast lattice. Employing atomic force microscopy, living hTERT-EECs were shown to produce extracellular matrix (ECM) components and ECM secretion was modified by estrogen and progesterone (P4). hTERT-EECs expressed inducible and functional endogenous estrogen receptor-alpha (ER-alpha) as demonstrated by estrogen response element reporter assays and induction of P4 receptor (PR). P4 treatment down-regulated PR expression, induced MUC-1 gene activity and resulted in increased ER-beta transcriptional activity. Gene activities of cytokines and their receptors interleukin (IL)-6, leukemia inhibitory factor (LIF), IL-11 and IL-6 receptor (IL6-R), LIF receptor and gp130 relevant to implantation revealed a 17 beta-estradiol (E2)-mediated up-regulation of IL-6 and an E2- and P4-mediated up-regulation of IL6-R in hTERT-EECs. Thus, hTERT-EECs may be regarded as a novel in vitro model to investigate the role of human EECs in steroid hormone-dependent normal physiology and pathologies, including implantation failure, endometriosis and endometrial cancer.

Demonstration of a non-steroidal, non-inhibin factor in the ovine corpus luteum of pregnancy that reduces pituitary responsiveness to GnRH-induced LH secretion in vitro

The decline in pulsatile LH secretion and pituitary responsiveness to GnRH as pregnancy advances may be due to non-steroidal factors secreted by the ovine corpus luteum of pregnancy. Corpora lutea from ten ewes on days 70-80 of gestation were homogenized, charcoal-treated and, together with charcoal-treated follicular fluid from superovulated women, were subjected to inhibin immunoaffinity chromatography, reducing dimeric inhibin A and B by >90% and abolishing inhibin bioactivity. These preparations were investigated using cultures of rat pituitary cells. GnRH-induced LH and FSH secretion in vitro was reduced by ovine corpus luteum extract and human follicular fluid by 47+/-5% and 42+/-5% of control LH and by 37+/-5% and 50+/-10% of control FSH, respectively (P<0.001). Extracts prepared from corpora lutea and placentae that were collected on days 50, 90 and 120 of pregnancy (five ewes per stage of pregnancy) showed increased GnRH-induced LH-suppressing bioactivity, particularly in the case of the placental extracts, with a threefold increase in activity. When partially purified by pseudochromatofocusing, GnRH-induced LH-suppressing bioactivity in extracts of ovine corpora lutea was identified at pH 5.40 and 5.77. Although these values are similar to published gonadotrophin surge-attenuating factor (GnSAF) bioactivity pI values, a GnSAF-blocking antiserum had no consistent effect on ovine corpus luteum extract GnRH-induced LH-suppressing bioactivity. It was concluded that the ovine corpus luteum of pregnancy contains a non-steroidal, non-inhibin factor, probably not GnSAF, that has the ability to reduce pituitary responsiveness to GnRH in vitro.

Effects of pregnancy on pulsatile secretion of LH and gonadotrophin-releasing hormone-induced LH release in sheep: a longitudinal study

Pulsatile LH secretion and its control throughout pregnancy have not been fully determined in sheep. Expt 1 determined the patterns of LH secretion in five ewes on days 10, 20, 60 and 120 of pregnancy and on day 10 postpartum, compared with those on day 10 of the oestrous cycle. Mean (+/- SEM) concentrations of LH declined steadily throughout pregnancy (ANOVA, P < 0.01) and were lower (P < 0.01) on day 60 (0.19 +/- 0.3 ng ml(-1)) and on day 120 (0.18 +/- 0.4 ng ml(-1)) of pregnancy than on day 10 of the oestrous cycle (0.55 +/- 0.04 ng ml(-1)). This decrease was due to a significant reduction in the number and the amplitude of LH pulses. Only on day 120 of pregnancy were progesterone concentrations higher (P < 0.01) than on day 10 of the oestrous cycle. Although concentrations of progesterone on day 10 postpartum were barely detectable, mean LH concentration (0.45 +/- 0.09 ng ml(-1)) was not different from that on day 10 of the oestrous cycle. Expt 2 examined the LH responses in a separate group of four ewes to a physiological dose of GnRH (0.2 microg) on days 10, 20, 60 and 120 of pregnancy and on day 10 postpartum, compared with those on day 10 of the oestrous cycle. The area under the LH response curve and the maximum LH concentrations induced by GnRH declined steadily throughout pregnancy (ANOVA, P < 0.01) and were lower (P < 0.01) on days 60 and 120 of pregnancy than on day 10 of the oestrous cycle, but these parameters were not different between day 10 postpartum and day 10 of the oestrous cycle. Expt 3 examined the LH responses in a separate group of four ewes to a potent GnRH agonist, buserelin (0.5 microg), on days 10, 60 and 120 of pregnancy. The area under the LH response curve and the maximum LH concentrations induced by GnRH were lower (P < 0.01) on days 60 and 120 than on day 10 of pregnancy, but were not different between days 60 and 120. This longitudinal study demonstrates that the pulsatile LH release and pituitary responsiveness to GnRH decreases progressively as pregnancy advances, but does not support the hypothesis that high concentrations of progesterone are solely responsible for the inhibition of pulsatile LH secretion and GnRH-induced LH release during pregnancy in sheep.

Effects of pregnancy on pulsatile secretion of LH and gonadotrophin-releasing hormone-induced LH release in sheep: a longitudinal study

Pulsatile LH secretion and its control throughout pregnancy have not been fully determined in sheep. Expt 1 determined the patterns of LH secretion in five ewes on days 10, 20, 60 and 120 of pregnancy and on day 10 postpartum, compared with those on day 10 of the oestrous cycle. Mean (+/- SEM) concentrations of LH declined steadily throughout pregnancy (ANOVA, P < 0.01) and were lower (P < 0.01) on day 60 (0.19 +/- 0.3 ng ml(-1)) and on day 120 (0.18 +/- 0.4 ng ml(-1)) of pregnancy than on day 10 of the oestrous cycle (0.55 +/- 0.04 ng ml(-1)). This decrease was due to a significant reduction in the number and the amplitude of LH pulses. Only on day 120 of pregnancy were progesterone concentrations higher (P < 0.01) than on day 10 of the oestrous cycle. Although concentrations of progesterone on day 10 postpartum were barely detectable, mean LH concentration (0.45 +/- 0.09 ng ml(-1)) was not different from that on day 10 of the oestrous cycle. Expt 2 examined the LH responses in a separate group of four ewes to a physiological dose of GnRH (0.2 microg) on days 10, 20, 60 and 120 of pregnancy and on day 10 postpartum, compared with those on day 10 of the oestrous cycle. The area under the LH response curve and the maximum LH concentrations induced by GnRH declined steadily throughout pregnancy (ANOVA, P < 0.01) and were lower (P < 0.01) on days 60 and 120 of pregnancy than on day 10 of the oestrous cycle, but these parameters were not different between day 10 postpartum and day 10 of the oestrous cycle. Expt 3 examined the LH responses in a separate group of four ewes to a potent GnRH agonist, buserelin (0.5 microg), on days 10, 60 and 120 of pregnancy. The area under the LH response curve and the maximum LH concentrations induced by GnRH were lower (P < 0.01) on days 60 and 120 than on day 10 of pregnancy, but were not different between days 60 and 120. This longitudinal study demonstrates that the pulsatile LH release and pituitary responsiveness to GnRH decreases progressively as pregnancy advances, but does not support the hypothesis that high concentrations of progesterone are solely responsible for the inhibition of pulsatile LH secretion and GnRH-induced LH release during pregnancy in sheep.

Effect of maternal undernutrition on fetal testicular steroidogenesis during the CNS androgen-responsive period in male sheep fetuses

The aim of this study was to determine the effects of maternal undernutrition, applied during physiologically relevant stages of development of the reproductive system, on reproductive development in male sheep fetuses. Groups of ewes (n = 11-19) were fed rations providing either 100% (high; H) or 50% (low; L) of metabolizable energy requirements for live weight maintenance during selected 'windows', bounded by days 0, 30, 50, 65 and 110 after mating. Ewes of control groups (HH (Expts 1 and 2) and HHH (Expt 3)) were fed the H ration from mating until they were killed at day 50 (Expt 1), day 65 (Expt 2) or day 110 (Expt 3) of gestation, whereas ewes of other groups were fed the L ration for the periods days 0-30 of gestation (LH and LHH), days 31-50 or days 31-65 of gestation (HL and HLH), days 65-110 of gestation (HHL), or day 0 to day 50, day 65 or day 110 of gestation (LL and LLL) when the animals were killed. At day 50 of gestation, there was no effect of nutritional treatment on mean fetal mass or fetal testicular mass, but there was increased expression of mRNA for steroidogenic acute regulatory protein (StAR) in the testes of LL animals (P < 0.05) compared with HH controls. Compared with HH animals, the mean plasma testosterone concentrations of LL fetuses tended to be higher, but this result did not reach significance. At day 65 of gestation there were no significant differences between treatments in mean fetal masses, testicular masses, mean plasma testosterone concentrations or StAR mRNA content. At day 110 of gestation, fetal masses in the LLL group were lower (P < 0.01) than those of control fetuses, although no differences in testicular size or fetal plasma testosterone concentrations were recorded. It is concluded that the effects of undernutrition on reproductive development of male sheep fetuses are dependent on the timing of the period of undernutrition.

Effect of maternal undernutrition on fetal testicular steroidogenesis during the CNS androgen-responsive period in male sheep fetuses

The aim of this study was to determine the effects of maternal undernutrition, applied during physiologically relevant stages of development of the reproductive system, on reproductive development in male sheep fetuses. Groups of ewes (n = 11-19) were fed rations providing either 100% (high; H) or 50% (low; L) of metabolizable energy requirements for live weight maintenance during selected 'windows', bounded by days 0, 30, 50, 65 and 110 after mating. Ewes of control groups (HH (Expts 1 and 2) and HHH (Expt 3)) were fed the H ration from mating until they were killed at day 50 (Expt 1), day 65 (Expt 2) or day 110 (Expt 3) of gestation, whereas ewes of other groups were fed the L ration for the periods days 0-30 of gestation (LH and LHH), days 31-50 or days 31-65 of gestation (HL and HLH), days 65-110 of gestation (HHL), or day 0 to day 50, day 65 or day 110 of gestation (LL and LLL) when the animals were killed. At day 50 of gestation, there was no effect of nutritional treatment on mean fetal mass or fetal testicular mass, but there was increased expression of mRNA for steroidogenic acute regulatory protein (StAR) in the testes of LL animals (P < 0.05) compared with HH controls. Compared with HH animals, the mean plasma testosterone concentrations of LL fetuses tended to be higher, but this result did not reach significance. At day 65 of gestation there were no significant differences between treatments in mean fetal masses, testicular masses, mean plasma testosterone concentrations or StAR mRNA content. At day 110 of gestation, fetal masses in the LLL group were lower (P < 0.01) than those of control fetuses, although no differences in testicular size or fetal plasma testosterone concentrations were recorded. It is concluded that the effects of undernutrition on reproductive development of male sheep fetuses are dependent on the timing of the period of undernutrition.

High omega-3:omega-6 fatty acid ratios in culture medium reduce endometrial-cell survival in combined endometrial gland and stromal cell cultures from women with and without endometriosis

OBJECTIVE

To study the effects of omega-3 and omega-6 polyunsaturated fatty acid (PUFA) on in vitro proliferation of endometrial cells and their production of the cytokine interleukin-8 (IL-8).

DESIGN

In vitro study.

SETTING

Obstetrics and gynecology department, University of Aberdeen.

PATIENT(S)

Women attending an infertility clinic.

INTERVENTION(S)

In vitro cell cultures using culture mediums supplemented with normal and high ratios of omega-3 PUFA and omega-6 PUFA.

MAIN OUTCOME MEASURE(S)

In vitro survival and production of IL-8 by dispersed endometrial cells.

RESULT(S)

In vitro survival of endometrial cells from women with and without endometriosis was significantly reduced in the presence of high omega-3:omega-6 PUFA ratios compared with cells incubated in the absence of fatty acids, in balanced omega-3:omega-6 PUFA ratios, and in high omega-6:omega-3 PUFA ratios. Endometrial cells from women with endometriosis secreted higher concentrations of IL-8, especially in the presence of high omega-3:omega-6 PUFA ratios.

CONCLUSION(S)

omega-3 PUFA may have a suppressive effect on the in vitro survival of endometrial cells and omega-3 PUFA be useful in the management of endometriosis by reducing the inflammatory response and modulating cytokine function.

Relationship between follicle size and gonadotrophin surge attenuating factor (GnSAF) bioactivity during spontaneous cycles in women

BACKGROUND

We have previously demonstrated that follicles < or =11 mm diameter from women undergoing IVF contain higher concentrations of gonadotrophin surge attenuating factor (GnSAF) bioactivity than large follicles from the same ovaries.

METHODS

To determine whether this finding is relevant to spontaneous cycles, follicular fluid aspirated from 37 follicles between 3 and 25 mm in diameter from 14 pairs of ovaries from regularly cycling women undergoing total abdominal hysterectomy and bilateral salpingoophorectomy for benign gynaecological disease was pooled into size categories (3 + 4, 5 + 6, 7 + 8, 9 + 10, 11 + 12, 14 + 15, 18 and 25 mm). These pools were bioassayed for GnSAF and inhibin-A, inhibin-B and activin-A concentrations were determined.

RESULTS

Follicles of 5 + 6 mm diameter contained the highest concentrations of GnSAF bioactivity (reducing GnRH-induced LH secretion to 38 +/- 8% of control, P < 0.001), while those of 25 mm diameter contained one quarter of this concentration (reducing GnRH-induced LH secretion to 72 +/- 2% of control, P < 0.05). GnSAF bioactivity was closely related to follicle size (r = -0.836, P < 0.01), but not to inhibin-A, inhibin-B or activin-A concentrations.

CONCLUSIONS

The finding that small follicles contain high concentrations of GnSAF bioactivity, which fall as folliculogenesis progresses during spontaneous cycles, support the hypothesis that GnSAF has a role in preventing the premature onset of the LH surge in women.

Endocrine disrupting chemicals: effects on human male reproductive health

There is now considerable evidence that male reproductive function is declining in human and wildlife populations. This is coincident with the increasing use and prevalence of man-made chemicals in the environment over the last fifty years. Certain chemicals have subsequently been shown to disturb the developing fetal endocrine system of laboratory animals in utero. In these experiments, treatment caused similar male reproductive problems in offspring as those already observed in wildlife and human populations. In addition, both the human DES data and rodent studies have shown that there are specific windows of gestation when the developing fetal gonad is highly sensitive to small endocrine changes. Animal in vivo and human in vitro studies have identified EDC sensitive genes. Consequently, hypotheses are being generated concerning mechanism of action e.g. disturbed testicular apoptosis and altered hepatic biotransformation of steroids. While animal studies provide us with valuable insights into the range of effects that can be attributed to in utero EDC exposure, varying maternal doses employed by different research groups make relation of the results to human observations difficult. The EDC concentration representative of fetal exposure levels is uncertain. Confounding factors include: (a) the vast number of chemicals termed EDCs, (b) the ability of chemicals to bioaccumulate in body lipid, (c) the metabolism of body lipid during pregnancy releasing the mothers lifetime EDC legacy into circulation and (d) the poorly understood kinetics of EDC transfer across the placenta. Thus, the level of fetal exposure can only be crudely estimated at present. This highlights the need for large animal models of EDC in utero exposure where the partitioning of EDCs between the mother and fetus and transfer across the placenta can be studied in detail. Despite considerable effort the mechanisms by which these endocrine disrupting chemicals exert their effects are still largely unknown. Further studies of the mechanism of action, and consequences, of EDCs in fetal development must be done in order to elucidate how EDCs exert their effects. This can only be achieved using a combined approach whereby animal models are used in combination with in vitro human studies. In conclusion however, there are now sufficient animal model data to prove that EDCs can adversely affect reproductive development and function in the male. Our further understanding of the mechanisms involved may allow intervention strategies whereby we can at least prevent a further decline in male as well as female reproductive health.

Human fetal testis: second trimester proliferative and steroidogenic capacities

The period of Leydig cell hyperplasia (14-18 weeks gestation) in human fetal testis is crucial for normal gonad development. We have studied the spatio-temporal distribution of key developmental and functional markers in human fetal testis between 13-19 weeks gestation. Proliferating cell nuclear antigen-positive cells were immunolocalized to both interstitium and tubules. Image analysis confirmed an increase in positive interstitial cells during Leydig cell hyperplasia (P: < 0.05). c-Myc was localized to the interstitium with no gestational changes. The steroidogenic enzymes 3beta-hydroxysteroid dehydrogenase (protein) and cytochrome P450 17alpha-hydroxylase/C(17-20)-lyase (P450c17; messenger ribonucleic acid and protein) were confined to the Leydig cells. The number of immunopositive cells increased between 13 and 19 weeks (P: < 0.001). P450c17 mRNA (in situ hybridization) and protein were localized to the same population of interstitial Leydig cells. Androgen receptor and Bcl-2 protein (anti-apoptotic) were gradually restricted to the peritubular myoid cells as gestation progressed. Conversely, Bax protein (pro-apoptotic) was predominantly localized to the tubule Sertoli cells, whereas the germ cells were Bax immunonegative. In conclusion, human fetal Leydig cell hyperplasia is characterized by increasing numbers of proliferating cells and increased expression of steroidogenic enzymes. The Bcl-2-positive, Bax-negative status of the peritubular myoid cells may be a strategy for cell survival.

A longitudinal study of maternal serum inhibin-A, inhibin-B, activin-A, activin-AB, pro-alphaC and follistatin during pregnancy

Maternal serum concentrations of inhibin-A, inhibin-B, activin-A, activin-AB, pro-alphaC-related inhibin forms, total follistatin, steroids and gonadotrophins were measured longitudinally in six normal singleton pregnancies. Maternal venous blood was collected randomly during a spontaneous follicular phase prior to donor insemination, at 5, 7, 9, 11, 16, 20, 24, 28, 32 and 36 weeks after the first missed menses and in the early puerperium. Steroid and gonadotrophin profiles conformed to previous reports. While at week 5 of gestation inhibin-A, activin-A and follistatin concentrations were similar to those at the follicular phase, all three increased progressively (P < 0.001) to maximal concentrations in week 36: approximately 48-fold (3740 +/- 1349 ng inhibin-A/ml), approximately 22-fold (6109 +/- 1443 ng activin-A/ml) and approximately 10-fold (3563 +/- 418 ng follistatin/ml) higher. Pro-alphaC concentrations reached a maximum in weeks 5 (approximately 5-fold, P < 0.001) and 36 (1027 +/- 174 pg/ml, P < 0.01). Inhibin-B (71 +/- 23 pg/ml prior to pregnancy) was undetectable (<12 pg/ml) between week 5-16 of gestation but increased slightly in the third trimester (26 +/- 7 pg/ml in week 36). Activin-AB was undetectable throughout pregnancy. Post-partum concentrations of inhibin-A (41 +/- 12 ng/ml), inhibin-B (<12 pg/ml), activin-A (950 +/- 149 pg/ml), pro-alphaC (128 +/- 22 pg/ml) and follistatin (990 +/- 79 ng/ml) were substantially lower than at week 36 of gestation. The activin-A:follistatin ratio increased from 0.5 in week 5 to 1.8 in week 36, suggesting that more free activin-A is available in the maternal circulation during late pregnancy.

Measurement of inhibin-A (alpha beta A dimer) during the oestrous cycle, after manipulation of ovarian activity and during pregnancy in ewes

A new two-site ELISA was validated for ovine plasma and used to measure circulating inhibin-A concentrations during a synchronized oestrous cycle in four ewes and throughout pregnancy in six ewes. Inhibin A concentrations were also determined in four ewes during chronic treatment with a GnRH agonist and after subsequent exposure to pregnant mares' serum gonadotrophin (PMSG) to stimulate ovarian follicular development. Concentrations of FSH, LH, oestradiol and progesterone were determined by radioimmunoassay. The detection limit of the inhibin-A ELISA was approximately 50 pg ml-1 and no significant crossreaction was observed with a range of related molecules including activin-A, inhibin-B, activin-B, follistatin and alpha 2-macroglobulin. Inhibin-A concentrations were below the detection limit in plasma from hypophysectomized and ovariectomized ewes. During the oestrous cycle, plasma inhibin-A concentrations (approximately 0.3-0.4 ng ml-1) did not vary during the follicular phase whereas plasma oestradiol increased approximately tenfold. After the preovulatory LH/FSH surge, inhibin-A fell to a nadir (approximately 0.15 ng ml-1) coincident with the peak of the postovulatory FSH rise. During the next 2 days, FSH concentrations fell to basal values as inhibin-A concentrations increased (P < 0.05) to a peak (approximately 0.5 ng ml-1) 3 days after the preovulatory LH/FSH surge. Over the following 3 days, FSH values increased again (P < 0.05) as inhibin-A concentrations fell to approximately 0.25 ng ml-1 (P < 0.05). Chronic GnRH agonist treatment suppressed FSH concentrations by about 50%, while inhibin-A and oestradiol concentrations fell below detection limits. Within 2 days after the PMSG injection, concentrations of inhibin-A (approximately 4.5 ng ml-1) and oestradiol (approximately 20 pg ml-1) had increased to very high values, while FSH concentrations had been reduced by a further 50%. Plasma concentrations of inhibin-A and FSH were similar to those in nonpregnant ewes during the first 60 days of gestation, but inhibin-A values fell markedly (sevenfold; P < 0.01) between days 60 and 90, coincident with a twofold decrease in FSH (P < 0.05). Inhibin A and FSH concentrations remained low for the remainder of gestation and were positively correlated throughout pregnancy (r = 0.48; P < 0.005). These observations support an endocrine feedback role for ovarian inhibin-A and oestradiol in controlling the secondary (postovulatory) FSH surge in ewes, but indicate that an increase in oestradiol is responsible for the characteristic reduction in FSH during the early to mid-follicular phase. The reduced secretion of FSH from mid- to late pregnancy cannot be attributed to increased inhibin-A secretion by the feto-placental unit, but most likely reflects increased steroid secretion from this source.

Follicle-stimulating hormone stimulates circulating gonadotropin surge-attenuating/inhibiting factor bioactivity in cows

This study aimed to determine whether superovulation in cattle stimulates gonadotropin surge-attenuating/inhibiting factor (GnSAF/IF) bioactivity, as it does in humans. Blood samples were collected from cows (n = 7 per treatment) at -4, 8, 20, 32, 44, 56, and 68 h after injections of saline, eCG, or FSH. Equal volumes of plasma at each treatment and time point were pooled, and GnSAF/IF and inhibin bioactivities were measured using an established rat pituitary cell culture bioassay. Plasma from saline- and eCG-treated cows had little effect on GnRH-induced LH secretion (116.3 +/- 8.3%-81.6 +/- 6.0% of control), while plasma from FSH-treated cows produced a time-dependent suppression of GnRH-induced LH secretion, falling to 64.6 +/- 4.0% of the control value at 56 h after first FSH injection (p < 0.001). The GnSAF/IF bioactivity from the 56-h plasma eluted at pH 5.73 by pseudochromatofocusing-similar to the GnSAF/IF isoelectric point value of 5.81 determined using serum from superovulated women. Plasma from FSH-treated cows reduced basal FSH secretion more than plasma from eCG-treated cows (to 55.5 +/- 5.7% and 63.2 +/- 6.6% of the control value, respectively, p < 0.01) although immunoreactive inhibin concentrations were similar between the two groups. We conclude that FSH, but not eCG, treatment causes a time-dependent production of circulating GnSAF/IF bioactivity in cattle.

Maternal pituitary gonadotroph function in relation to GnRH receptor and LH beta mRNA content during pregnancy in ewes

To investigate the mechanism controlling the fall in maternal pituitary responsiveness to GnRH, LH synthesis and pituitary GnRH receptor content during pregnancy, maternal pituitaries were collected from sheep on days 35, 45, 60, 90, 110, 125 and 135 of pregnancy. Circulating steroids and gonadotrophins were determined in blood samples collected from these ewes immediately before death. Pituitary blocks from each ewe were perifused with either medium alone (control) or medium supplemented with oestradiol, oestradiol plus progesterone or oestradiol plus RU486, for 150 min before administration of two 15 s GnRH pulses 90 min apart. The amounts of mRNA encoding LH beta and GnRH receptor were determined in pituitary tissue fragments snap-frozen in liquid N2 at the time of collection from the ewes. While basal LH secretion fell during pregnancy, pituitary responsiveness to GnRH remained high (up to seven times basal LH concentrations). After day 90, the first GnRH pulse elicited LH peaks equivalent to the LH peaks produced by the second GnRH pulse. Therefore, GnRH self-priming was not evident possibly because the pituitaries were constantly primed by increased concentrations of maternal oestradiol. Around day 90, circulating concentrations of progesterone rose from 7.8 +/- 1.5 to 12.2 +/- 3.8 ng ml-1. Up to day 60, oestradiol in the perifusion buffer had stimulatory effects on LH secretion although this was reduced by RU486. By day 125, the content of mRNA encoding LH beta had declined during pregnancy to 7% of the content on day 35, although the content of mRNA encoding GnRH receptor remained unchanged. From these data, there appears to be a transitional period at around day 90 of gestation when pituitary sensitivity to steroids in vitro is lost together with detectable GnRH self-priming. In conclusion, the marked decline in pituitary amounts of mRNA encoding LH beta, but not in GnRH responsiveness or expression of GnRH receptor, after day 45 of pregnancy suggests that the principal effect of pregnancy on gonadotroph function is mediated via a mechanism other than reduced pituitary amounts of GnRH receptors. Two possible mechanisms are (1) a reduction in GnRH output leading to lowered LH synthesis, or (2) the presence of an inhibitory factor with a short half-life in the maternal circulation.

Safety, tolerability, and pharmacokinetics of sumatriptan suppositories following single and multiple doses in healthy volunteers

A suppository formulation of the 5HT1 agonist sumatriptan could prove an important therapeutic option in migraine patients who dislike or poorly tolerate injectable therapy and where oral tablet administration is unsuitable because of severe migraine-related vomiting. Two independent double-blind, randomized clinical studies were conducted to evaluate the safety, tolerability and pharmacokinetics of sumatriptan suppositories following ascending single doses (four different dose levels) and multiple doses. In the four-period, crossover, single-dose study, 24 healthy male subjects were randomized to receive a suppository containing 12.5, 25, 50, or 100 mg on separate occasions 3-14 days apart. The suppositories were generally well tolerated; transient asthenia, drowsiness, and headache were the most frequently reported adverse events, and these were not dose-related. Peak plasma concentrations (Cmax) of sumatriptan were proportional to dose from 25 to 100 mg; area under the plasma concentration-time curve (AUC infinity) values were proportional to dose except at the highest doses, when they were greater than those predicted from lower doses. For all doses, the tmax of sumatriptan occurred within 2.5 h, and the t1/2 was approximately 2 h. In the two-period, placebo-controlled, crossover, repeat-dose study, 12 healthy adult male subjects were randomized to receive either a 50-mg sumatriptan suppository or placebo suppository, administered rectally twice a day, for 11 doses (5 1/2 days). Adverse events were no more frequent with sumatriptan than with placebo, and stool guaiac, rectal examinations, and physical examinations remained normal. No significant differences were noted between Day 1 and Day 6 values in the AUC, Cmax, time of peak serum concentration (tmax), elimination half-life (t 1/2), fraction of the dose excreted in the urine (fe), or renal clearance (Clr) of sumatriptan or its pharmacologically inactive indole acetic acid metabolite. Serum metabolite concentrations were two to three-fold higher than corresponding sumatriptan concentrations. No clinically significant accumulation of sumatriptan or its metabolite occurred. Overall, these studies show that sumatriptan administration via a suppository formulation is well tolerated, allows rapid absorption of sumatriptan, results in sumatriptan Cmax values that are proportional to dose from 25 to 100 mg, and is not associated with accumulation of sumatriptan or its metabolite.

Pharmacokinetic and pharmacodynamic profiles of sumatriptan in migraine patients with headache recurrence or no response

OBJECTIVES

Sumatriptan is effective in the acute treatment of migraine. However, about 15% of patients with migraine do not experience headache relief after sumatriptan, and up to 40% may experience recurrence of headache within 24 hours. We studied whether pharmacokinetic or pharmacodynamic differences may explain these different clinical effects.

METHODS

We compared the pharmacokinetic profiles of subcutaneous sumatriptan in 14 patients who consistently had headache relief without headache recurrence, in 12 patients who had headache recurrence in every attack, and in six patients who did not have headache relief after sumatriptan. Because the antimigraine action of sumatriptan may be mediated through vasoconstriction of cranial blood vessels, we also compared in these patients changes in blood vessel diameter and blood velocity in the common, internal, and external carotid arteries.

RESULTS

Despite sufficient power of the study, no important differences in pharmacokinetic and pharmacodynamic profiles between the three patient groups were detected.

CONCLUSION

Headache recurrence and lack of headache relief after sumatriptan do not appear to be explained by pharmacokinetic or pharmacodynamic differences between patients, which may be an important finding for the development of novel antimigraine drugs.

Changes in peripheral serum levels of total activin A during the human menstrual cycle and pregnancy

The main objective of this study was to determine whether activin A concentrations in peripheral blood fluctuate during the normal human menstrual cycle and pregnancy. Blood samples were collected longitudinally from five regularly cycling volunteers (22-30 yr) throughout a spontaneous menstrual cycle and cross-sectionally from normal pregnant women attending the antenatal clinic (8-38 weeks gestation: 3-20 subjects/time point). Total (i.e. bound plus free) activin A concentrations were measured using a recently developed two-site enzyme immunoassay that employs an analyte denaturation/oxidation step to eliminate interference due to endogenous activin-binding proteins. During the menstrual cycle, mean serum activin A levels varied in a biphasic manner (by ANOVA, P = 0.02), with highest levels around midcycle (approximately 220 pg/mL) and the late luteal/early follicular phase (approximately 310 pg/mL) and nadirs in both midfollicular (approximately 125 pg/mL) and midluteal (approximately 120 pg/mL) phases. Between the mid- to late luteal phase, the activin A level increased progressively (approximately 2.5-fold; P < 0.05), whereas inhibin A, estradiol, and progesterone all decreased progressively (approximately 10-fold; P < 0.001). During pregnancy, serum activin A levels were much higher than those in nonpregnant subjects, with a value of 2.12 +/- 0.31 ng/mL recorded in week 8. Levels remained at approximately 2 ng/mL between weeks 8-24, but increased thereafter to reach 25.5 +/- 6 ng/mL by week 38, a value approximately 100 times greater than that during the normal menstrual cycle. Serum activin A levels during pregnancy were significantly correlated with inhibin A (r = 0.69; P < 0.001), estradiol (r = 0.55; P < 0.001), and progesterone (r = 0.74; P < 0.001) values. Gel permeation chromatography indicated that all of the detectable activin A in human follicular fluid, pregnancy serum, and term placental extract eluted with an apparent molecular mass between 70-200 kDa, indicating that little, if any, free activin (molecular mass, 25 kDa) is present in these samples. Although these results support a possible endocrine role for circulating activin A during the human menstrual cycle and pregnancy, the observation that all detectable activin A is associated with binding protein(s) raises questions about its relative bioavailability for action on peripheral target cells.

The effects of steroidal and non-steroidal ovarian hormones on pituitary responsiveness to gonadotrophin surge-attenuating factor

Primary pituitary cultures from adult female rats were used to investigate the effects of steroidal (oestradiol and progesterone) and non-steroidal (inhibin, follistatin) ovarian hormones on the suppressive actions of the ovarian factor gonadotrophin surge-attenuating factor (GnSAF) in the control of gonadotrophin secretion. The source of GnSAF was a chromatographic preparation from follicular fluid containing four distinct protein bands as resolved on SDS-PAGE. Oestradiol and progesterone added alone had no effect on gonadotrophin secretion but had a wide range of effects on the suppression of both LH and FSH secretion caused by the non-steroidal factors. Oestradiol, progesterone and oestradiol+progesterone enhanced the suppressive actions of GnSAF on GnRH-induced LH secretion (causing 19.3 +/- 5.2% (P < 0.05), 41.9 +/- 3.4% (P < 0.001) and 32.2 +/- 5.3% (P < 0.001) greater suppression than GnSAF alone). Progesterone and oestradiol+progesterone completely abolished the suppression of basal FSH secretion caused by inhibin (causing 157.1 +/- 22.2%, P < 0.001, and 160.9 +/- 11.3%, P < 0.001, stimulation compared with inhibin alone). Separately the steroids had no effect on the suppression of gonadotrophin secretion caused by follistatin. However, in combination, oestradiol+progesterone potentiated the suppressive actions of follistatin on GnRH-induced LH secretion causing 29.9 +/- 5.3% (P < 0.05) greater suppression than follistatin alone. In combination, high-dose follistatin and GnSAF caused 31.1 +/- 6.5% (P < 0.01) greater suppression than GnSAF alone. Thus in combination high-dose follistatin and GnSAF have additive effects on the suppression of GnRH-induced LH secretion. Recombinant human inhibin and GnSAF added in combination had little further effect compared with either alone suggesting that they may have a similar mechanism of action at the pituitary level. These results demonstrate that while FSH secretion in vitro is mainly controlled by inhibin and follistatin, LH secretion is affected by the presence of a whole range of factors. We have demonstrated that oestradiol and progesterone potentiate the suppressive actions of GnSAF in vitro. These data are compatible with the suggestion that in the late follicular phase it is falling levels of GnSAF that allow positive feedback of the steroids on the pituitary to elicit the LH surge, rather than increases in the stimulatory effects of the ovarian steroids overcoming GnSAF. The actions of GnSAF on the pituitary may be modulated by follistatin but it is unlikely that inhibin has any modulatory effects on the GnSAF-induced suppression of LH secretion.

Role of progesterone and nonsteroidal ovarian factors in regulating gonadotropin-releasing hormone self-priming in vitro

We investigated the effects of gonadotropin surge-attenuating factor (GnSAF), inhibin, and follistatin on GnRH self-priming and its augmentation by progesterone. Two GnRH challenges, 60 min apart, were administered to rat pituitary monolayers after 90-min exposure to medium alone (control), progesterone, GnSAF, inhibin, or follistatin. Inhibin-stripped follicular fluid from superovulated women was used as a source of GnSAF bioactivity. Under control conditions, the greater response to the second GnRH challenge (peak 2, 9.2 +/- 2.1; peak 1, 4.4 +/- 0.9 ng LH/mL; P < 0.01) demonstrated GnRH self-priming. None of the treatments significantly altered the first LH peak. Progesterone markedly increased GnRH self-priming (peak 2, 12.6 +/- 2.5 ng LH/mL; P < 0.01). However, GnSAF and RU486 significantly reduced GnRH self-priming (peak 2, 4.6 +/- 0.9 and 5.6 +/- 1.6 ng LH/mL, respectively; P < 0.01). The augmentation of self-priming induced by progesterone was completely abolished by coincubation with either GnSAF or RU486 (peak 2, 7.5 +/- 1.6 and 4.3 +/- 0.9 ng LH/mL, respectively; P < 0.01). Neither inhibin nor follistatin had any effect on GnRH self-priming or its augmentation by progesterone. The actions of RU486 in the presence and absence of progesterone demonstrate a nonprogestagenic effect of RU486 on the gonadotropes. In conclusion, the suppression of GnRH self-priming, with or without progesterone augmentation, supports the hypothesis that GnSAF acts by maintaining the pituitary in an unprimed state of reduced responsiveness to GnRH.

Measurement of serum concentrations of inhibin-A (alpha-beta A dimer) during human pregnancy

OBJECTIVE

The aims were to measure concentrations of inhibin-A (alpha-beta A dimer) in peripheral serum during normal human pregnancy, to establish which molecular weight form(s) are present in pregnancy serum and to relate the concentrations of inhibin-A to those of oestradiol and progesterone.

DESIGN

In a retrospective cross-sectional study 211 serum samples collected at 2-week intervals from week 8 to 38 of gestation were analysed for inhibin-A by enzyme immunoassay and oestradiol and progesterone by radioimmunoassay. Pooled samples corresponding to first, second and third trimester were subsequently used for fast protein liquid chromatography chromatographic analysis of inhibin forms present.

PATIENTS

Blood samples were obtained from normal pregnant women attending the antenatal clinic.

RESULTS

Concentrations of inhibin-A in peripheral serum gradually decreased from 1.76 +/- 0.15 microgram/l in week 8 of gestation to 0.86 +/- 0.12 microgram/l in week 16 (P < 0.01). Concentrations remained low during the second trimester but increased markedly (P < 0.01) during the third trimester reaching a maximal value of 5.68 +/- 0.89 microgram/l in week 36. Chromatographic analysis of pooled serum samples from the first, second and third trimester showed that the fully processed 31-kDa molecule is the predominant circulating form of inhibin-A throughout human gestation. Likewise, only the 31-kDa form was identified in extracts of term placenta which contained approximately 20 micrograms inhibin-A/kg tissue.

CONCLUSION

Inhibin-A, principally the 31-kDa form, is present in peripheral blood throughout human gestation at concentrations up to 50 times greater than maximum values found during the spontaneous menstrual cycle (approximately 100 ng/l). The finding of highest serum values during the third trimester and of significant concentrations in term placenta firmly support a placental rather than luteal origin for this material.

The effects of oral sumatriptan, a 5-HT1 receptor agonist, on circulating ACTH and cortisol concentrations in man

1. The effects of oral sumatriptan (50, 100 and 200 mg), a 5-HT1 receptor agonist, and placebo, on circulating adrenocorticotrophic hormone (ACTH) and cortisol concentrations were determined over 24 h after dosing, in 26 healthy male subjects. ACTH was measured by immunoradiometric assay and cortisol by radioimmunoassay. 2. After sumatriptan all subjects displayed a normal diurnal rhythm for circulating ACTH and cortisol compared with placebo. 3. There was a reduction in the trough circulating ACTH concentration over 0-4 h which was 18% with 100 mg (P = 0.002), and 25% with 200 mg (P < 0.001). The 5 h, post-prandial, peak ACTH concentration was reduced by 21% with 100 mg (P = 0.018) and by 20% with 200 mg (P = 0.024). The weighted mean ACTH over 24 h was reduced by 8% with 100 mg (P = 0.029) and by 8% with 200 mg (P = 0.018). The nadir concentration of ACTH over the 24 h and the ACTH concentration 24 h after sumatriptan were not, however, significantly reduced. All results are compared with placebo. 4. There was a reduction in the trough circulating cortisol concentration over 0-4 h which was 15% with 50 mg (P = 0.015), 14% with 100 mg (P = 0.022) and 24% with 200 mg (P < 0.001). The 5 h, post-prandial, peak cortisol concentration was reduced by 16% with 100 mg (P = 0.012) and by 15% with 200 mg (P = 0.017).(ABSTRACT TRUNCATED AT 250 WORDS)

Single dose pharmacokinetics of sumatriptan in healthy volunteers

Sumatriptan is classified as a vascular 5HT1 receptor agonist and is effective in the acute treatment of migraine and cluster headache. Sumatriptan is available as an injection for subcutaneous administration and as a tablet for oral administration. The pharmacokinetics of sumatriptan differ depending on the route of administration. The mean subcutaneous bioavailability is 96% compared to 14% for the oral tablet. The lower bioavailability following oral administration is due mainly to presystemic metabolism. The inter-subject variability in plasma sumatriptan concentrations is greater following oral administration and a faster rate of absorption of drug into the systemic circulation is achieved following subcutaneous dosing. The pharmacokinetics of sumatriptan are linear up to a subcutaneous dose of 16 mg. Following oral dosing up to 400 mg, the pharmacokinetics are also linear, with the exception of rate of absorption, as indicated by a dose dependent increase in time to peak concentration. Sumatriptan is a highly cleared compound that is eliminated from the body primarily by metabolism to the pharmacologically inactive indoleacetic acid analogue. Both sumatriptan and its metabolite are excreted in the urine. Although the renal clearance of sumatriptan is only 20% of the total clearance, it exceeds the glomerular filtration rate, indicating that sumatriptan undergoes active renal tubular secretion. Sumatriptan has a large apparent volume of distribution (170 l) and an elimination half-life of 2 h. Oral doses of sumatriptan were administered as a solution of dispersible tablets and subcutaneous dosing was by injection into the arm. In clinical practice, sumatriptan is administered as a film coated tablet or by subcutaneous injection into the thigh.

Gonadotrophin surge-attenuating factor bioactivity is present in follicular fluid from naturally cycling women

Rat pituitary monolayer bioassays were used to compare gonadotrophin surge-attenuating factor (GnSAF) bioactivity in follicular fluid from 12 follicles in 10 spontaneously cycling women with that in pooled follicular fluid from women undergoing ovulation induction. Expressed as ED50S (microliter follicular fluid/well producing 50% of maximal effect), GnSAF bioactivity was detectable in all spontaneous follicular fluid samples (1.4-33.3 microliters/well) and in follicular fluid from women undergoing ovulation induction (6.8 microliters/well). This GnSAF bioactivity was unaffected by pre-incubation with an inhibin antibody. When the data were grouped according to whether the recovered oocytes fertilized in vitro or not, the fertilized group contained significantly greater GnSAF bioactivity than the unfertilized group (5.3 +/- 1.1 and 14.1 +/- 2.6 microliters/well respectively, P < 0.05). While both inhibin bioactivity (9.7 +/- 1.4 and 28.9 +/- 12.1 microliters/well) and immunoreactivity (36.8 +/- 2.2 and 21.0 +/- 3.0 and ng/ml) were also greater (P < 0.01) in the fertilized compared with the unfertilized groups respectively, there were no other significant differences between the two groups. We conclude that GnSAF is found in follicular fluid from spontaneously cycling women, supporting in-vivo evidence for the involvement of GnSAF in feedback control of the ovary-pituitary axis.

Gonadotropin surge-attenuating factor bioactivity in serum from superovulated women is not blocked by inhibin antibody

Primary pituitary cultures from adult female rats were used to investigate gonadotropin surge attenuating factor (GnSAF) bioactivity. Serum from superovulated women was charcoal-treated and incubated with either an inhibin antibody (MC4), normal sheep serum (NSS), or serum-free defined medium (SFDM) before addition to cell culture. The reduction in GnRH-induced LH secretion (GnSAF bioactivity) produced by the serum (30.1 +/- 6.5%, p < 0.001, of control) was not altered by prior incubation with either MC4 or NSS (24.9 +/- 3.6 and 23.2 +/- 2.7%, p < 0.001, of control, respectively). This indicates that GnSAF bioactivity present in serum from superovulated women is not entirely attributable to inhibin. Recombinant human inhibin reduced basal FSH secretion to 24.6 +/- 4.7% (p < 0.001) of the control value. However, this was totally abolished by prior incubation with MC4, but not NSS. We have also shown that ovarian steroids are not responsible for GnSAF bioactivity in vitro. In conclusion, in contrast to findings in superovulated rats, inhibin antibody did not block GnSAF bioactivity in serum from superovulated women.

Circulating gonadotrophin surge-attenuating factor from superovulated women suppresses in vitro gonadotrophin-releasing hormone self-priming

A perifusion system based on ovine pituitary tissue explants was used to investigate the effects of follicular fluid (hFF) and serum from superovulated women on pituitary responsiveness to gonadotrophin-releasing hormone (GnRH). The specific aims of the study were to determine both if gonadotrophin surge-attenuating factor (GnSAF) bioactivity is present in the peripheral circulation as well as in the follicles of superovulated women and if GnSAF suppresses GnRH self-priming in vitro. Two pulses of GnRH, 1 h apart, produced marked peaks in LH secreted from control chambers, with GnRH self-priming evident in the significant difference between the first (134.4 +/- 1.7 - 232.1 +/- 24.0% of basal secretion) and second (183.9 +/- 15.8 - 313.9 +/- 14.0% of basal secretion) LH peaks. Both follicular fluid and serum pooled from two different groups of women produced marked suppression of the first (unprimed) and second (primed) LH peaks. The hFF reduced the first LH peak to 69.6 +/- 7.8 and 60.2 +/- 9.7% and the second LH peak to 57.4 +/- 6.7 and 42.6 +/- 6.5% of control LH secretion. Overall, the serum reduced the first and second LH peaks to 76.8 +/- 4.2 and 62.9 +/- 3.6% of control respectively. These results demonstrated that GnSAF bioactivity suppresses GnRH self-priming, and is present in both the peripheral circulation and hFF. The same material administered to dispersed ovine pituitary monolayers produced similar marked suppression of GnRH-induced LH secretion, with approximately 50-fold less GnSAF bioactivity in serum compared with hFF. Combined doses of oestradiol and progesterone, or hFF from large follicles containing little GnSAF, produced stimulation of GnRH-induced LH secretion and GnRH self-priming (second peaks 78.1 +/- 38.9 and 27.4 +/- 15.7% respectively higher than first peaks). Thus, in conclusion, GnSAF in hFF and serum markedly attenuated both unprimed and primed pituitary response to GnRH, virtually abolishing the GnRH self-priming effect.

Higher gonadotrophin surge-attenuating factor bioactivity is found in small follicles from superovulated women

Ovine and rat pituitary bioassays for gonadotrophin surge-attenuating factor (GnSAF) were utilized to determine whether the level of GnSAF bioactivity in pooled human follicular fluid (hFF) from superovulated women varied according to follicle diameter (< or = 11 mm, 12-15 mm and 16-21 mm follicles examined using the ovine bioassay, or < or = 10 mm, 11-13 mm, 14-17 mm, 18-20 mm, 21-24 mm and > or = 25 mm follicles examined using the rat bioassay). When tested using dispersed ovine pituitary cells, GnSAF bioactivity, expressed in terms of the reduction in gonadotrophin-releasing hormone (GnRH)-induced LH secretion, was inversely related to follicle diameter (P < 0.01). In response to 5 microliters hFF/well from follicles of < or = 11, 12-15 and 16-21 mm diameter, GnRH-induced LH secretion was reduced to 40.5 +/- 6.9%, 65.2 +/- 6.6% and 83.7 +/- 7.9% of control respectively. A similar inverse relationship was observed when a second batch of hFF samples from different sized follicles was tested using rat pituitary cell monolayers. Expressing GnSAF bioactivity in terms of the dose required to suppress GnRH-induced LH secretion by rat pituitary cells to 50% of the maximal suppression observed (ED50), the three smallest follicle size pools contained the most GnSAF (ED50 values of 0.13, 2.79 and 5.36 microliters hFF/well from follicles of < or = 10, 11-13 and 14-17 mm respectively). The ED50 values for follicles of 18-20, 21-24 and > or = 25 mm were 8.81, 27.1 and 60.0 microliters hFF/well respectively. Thus hFF from follicles < or = 11 mm was over 450 times more potent than hFF from follicles > or = 25 mm in suppressing GnRH-induced LH release. The ED50 values for inhibin bioactivity (measured as the suppression of basal FSH secretion from rat pituitary monolayers) were much less variable than those for GnSAF bioactivity (between 0.85 and 0.13 microliters hFF/well). Inhibin immunoreactivity, measured by a two-site immunoradiometric assay, followed the same pattern as inhibin bioactivity with lowest concentrations in the smallest follicles (41.96 ng/ml) and highest concentrations in the three largest follicle size groups (56.48-64.48 ng/ml). The specific effects of inhibin on GnRH-induced LH and basal FSH release in these pituitary bioassays were determined by incubating culture dishes with pure recombinant human inhibin at doses of 0.025-25 ng/well. In both the sheep and rat pituitary monolayers, basal FSH was suppressed (ED50 = 0.02 and 0.16 ng/well respectively).(ABSTRACT TRUNCATED AT 400 WORDS)

Serum concentrations of dimeric inhibin during the spontaneous human menstrual cycle and after treatment with exogenous gonadotrophin

A recently described two-site enzyme immunoassay incorporating a pre-assay oxidation step was validated and used to measure serum concentrations of dimeric inhibin in five normally cycling women and in 13 women undergoing gonadotrophin therapy. Recombinant human inhibin A (standard) gave an assay response curve which was parallel to those for human serum samples and recovery of exogenous inhibin added to serum samples before assay was quantitative (109 +/- 8%, n = 11). During the normal menstrual cycle dimeric inhibin concentration increased from 9.0 +/- 2.0 pg/ml during the early follicular phase to reach a mid-cycle peak of 55.3 +/- 11.1 pg/ml coincident with the pre-ovulatory gonadotrophin surge. After falling to 27.9 +/- 5.7 pg/ml 1 day after the luteinizing hormone surge, inhibin then rose in parallel with serum progesterone to reach a peak value of 115.6 +/- 19.3 pg/ml during the mid-luteal phase, before falling to 14.1 +/- 4.9 pg/ml by the onset of next menses. During the follicular phase, dimeric inhibin concentrations were closely correlated with those of serum oestradiol (r = 0.69; P < 0.001), whereas during the luteal phase they were most closely correlated with serum progesterone concentrations (r = 0.73; P < 0.001). Daily treatment with human menopausal gonadotrophin promoted a progressive increase in serum dimeric inhibin concentration which increased approximately 20-fold in 6 days. In the same period total alpha-inhibin (measured by radioimmunoassay) increased approximately 5-fold, while serum oestradiol increased approximately 30-fold.(ABSTRACT TRUNCATED AT 250 WORDS)

Imaging techniques for the assessment of body composition

Three imaging methods, ultrasound imaging (UI), computer-assisted axial tomography (CAT) and magnetic resonance imaging (MRI), are widely used in medicine. Their application to the assessment of body composition in nutrition research is still being explored and developed. Ultrasound imaging yields poor image quality but, because it is cheap and safe, deserves further exploration. Both CAT and MRI can produce images with good discrimination among bone, muscle and adipose tissue. Movement artifacts tend to be more serious in MRI than in CAT due to the longer imaging time. On the other hand, the X-ray exposure in CAT is likely to limit its use in human nutrition research. Repeated measurements of tissue volumes by CAT and MRI give similar CV. In both CAT and MRI, intra-abdominal adipose tissue presents greater problems of measurement than subcutaneous adipose tissue. Validation studies with 77-kg pigs of MRI, using 13 slices, predicted total body lipid with residual standard deviation of 1.9%. In validating any of these methods, account should be take of the extent to which the information they give can augment that given by more simple measures like age and weight.

The ovarian modulation of gonadotrophin releasing hormone-induced luteinizing hormone secretion in women

Ovine pituitary cell culture and perfusion bioassays were used to investigate gonadotrophin surge-attenuating factor (GnSAF) bioactivity in vitro. GnSAF is present in steroid-free human follicular fluid (HFF) from superovulated women and specifically attenuates gonadotrophin releasing hormone (GnRH)-induced luteinizing hormone (LH) secretion. HFF produced dose-dependent suppression of GnRH-induced LH and basal FSH secretion, the former reflecting GnSAF bioactivity, the latter inhibin bioactivity. Heparin-Sepharose chromatography of HFF removed inhibin bioactivity, but not GnSAF bioactivity, indicating that these are distinct entities. Ultrafiltration of HFF suggests that GnSAF has a bioactive form of 10-30 kDa. Ovine pituitary perfusion demonstrated that GnSAF bioactivity in HFF is matched in the serum of superovulated and pregnant women. In addition, HFF and serum suppress both the initial and reserve pools of GnRH-induced LH secretion and greatly reduce the self-priming effect of GnRH in ovine pituitary tissue perfusion. In-vitro and in-vivo GnSAF bioactivity is consistent with a role for GnSAF in the gonadal feedback regulation of pituitary response to GnRH.

Effects of gonadotrophin surge-attenuating factor on the two pools of gonadotrophin-releasing hormone-induced luteinizing hormone secretion in vitro

In order to study the in-vitro mechanism of action of gonadotrophin surge-attenuating factor (GnSAF), ovine pituitary monolayers were incubated for 48 h either with steroid-free follicular fluid from women in whom ovulation had been induced or oestradiol or progesterone. Monolayers were also incubated with 10-30 and > 30 kDa follicular fluid fractions. The effect of these preparations on gonadotrophin-releasing hormone (GnRH)-induced luteinizing hormone (LH) secretion was then determined by incubation with GnRH for between 15 and 240 min. Incubation with steroid-free follicular fluid resulted in the significant attenuation of both the acutely releasable LH pool (LH 54.3 +/- 3.0% of control secretion at 15 min of GnRH incubation) and the reserve LH pool (LH 36.8 +/- 1.6% of control secretion at 240 min GnRH incubation). The 10-30 kDa follicular fluid fraction had similar effects while the > 30 kDa follicular fluid fraction significantly stimulated GnRH-induced LH secretion, with concentrations up to 134.0 +/- 8.6% of controls. Oestradiol or progesterone at doses of 1000 nmol/l/well did not significantly reduce any aspect of GnRH-induced LH secretion (never < 95.1 +/- 15.1% of controls). These results demonstrate that GnSAF markedly attenuates both the acutely releasable and reserve pools of GnRH-induced LH secretion. Inhibin, oestradiol and progesterone are not responsible for the marked attenuation of either the initial or reserve pools of GnRH-induced LH secretion.

Gonadotrophin surge-attenuating factor attenuates in-vitro LH secretion induced by gonadotrophin-releasing hormone from cultured ovine pituitary cells only during the breeding season

Primary cultures of ovine pituitaries from adult ewes were used to investigate aspects of gonadotrophin surge-attenuating factor (GnSAF) bioactivity in human follicular fluid (hFF) from superovulated women. During the autumn and first half of the winter, LH secretion induced by gonadotrophin-releasing hormone (GnRH) was markedly reduced (43.5 +/- 5.2% of control GnRH-induced LH secretion) by incubation for 48 h with steroid-free hFF. For the rest of the year, treatment with the same batch of steroid-free hFF resulted in non-significant reduction or stimulation of GnRH-induced LH secretion (71.3 +/- 13.2 to 117.8 +/- 11.2% of control GnRH-induced LH secretion). Incubation of pituitary cells for 48 h with oestradiol (1 pmol/l to 1 mumol/l), progesterone (1 pmol/l to 1 mumol/l) or oestradiol and progesterone combined (1 pmol/l to 1 mumol/l) in a two-way titration for 48 h had no significant effect on GnRH-induced LH secretion (83.4 +/- 7.6 to 110.6 +/- 5.0% of control secretion). Separating hFF into fractions of different molecular mass by ultrafiltration demonstrated that GnSAF bioactivity was present in a form 10-30 kDa in size. Incubation for 48 h with these fractions had no significant effect on basal FSH secretion but significantly attenuated GnRH-induced LH secretion during the autumn. The same fractions had little effect on GnRH-induced LH secretion from pituitary cells collected during the summer. We conclude that ovine pituitaries display at least partial reduction in sensitivity to GnSAF outside the breeding season.(ABSTRACT TRUNCATED AT 250 WORDS)