Increased plasma concentration of N-terminal beta-lipotrophin and unbound cortisol during pregnancy

Adrenal insufficiency in pregnancy: Physiology, diagnosis, management and areas for future research

Adrenal insufficiency requires prompt diagnosis in pregnancy, as untreated, it can lead to serious consequences such as adrenal crisis, intrauterine growth restriction and even foetal demise. Similarities between symptoms of adrenal insufficiency and those of normal pregnancy can complicate diagnosis. Previously diagnosed adrenal insufficiency needs monitoring and, often, adjustment of adrenal hormone replacement. Many physiological changes occur to the hypothalamic-pituitary-adrenal (HPA) axis during pregnancy, often making diagnosis and management of adrenal insufficiency challenging. Pregnancy is a state of sustained physiologic hypercortisolaemia; there are multiple contributing factors including high plasma concentrations of placental derived corticotropin-releasing hormone (CRH), adrenocorticotropin (ACTH) and increased adrenal responsiveness to ACTH. Despite increased circulating concentrations of CRH-binding protein (CRH-BP) and the major cortisol binding protein, corticosteroid binding globulin (CBG), free concentrations of both hormones are increased progressively in pregnancy. In addition, pregnancy leads to activation of the renin-angiotensin-aldosterone system. Most adrenocortical hormone diagnostic thresholds are not applicable or validated in pregnancy. The management of adrenal insufficiency also needs to reflect the physiologic changes of pregnancy, often requiring increased doses of glucocorticoid and at times mineralocorticoid replacement, especially in the last trimester. In this review, we describe pregnancy induced changes in adrenal function, the diagnosis and management of adrenal insufficiency in pregnancy and areas requiring further research.

Alopecia in rhesus macaques (Macaca mulatta): Association with pregnancy and chronic stress

BACKGROUND

Alopecia in captive non-human primates is often presented as a welfare issue. However, it is a complex condition with a number of possible causes. The purpose of this study was to assess the impact of pregnancy and hair cortisol concentrations on alopecia in rhesus macaques.

METHODS

Subjects were 113 socially housed adult female rhesus macaques (27 pregnant, 35 nursing infants, 51 controls). During routine physicals, photographs were taken for alopecia assessment and hair samples were collected for cortisol assay.

RESULTS

Alopecia was more prevalent in pregnant than in control females, but there was no association between alopecia and hair cortisol. However, there was a significant effect of pregnancy on hair cortisol. Nursing females had higher hair cortisol levels than pregnant females, which had higher levels than control females.

CONCLUSIONS

Although alopecia does not appear to be associated with hair cortisol, both alopecia and hair cortisol were associated with pregnancy.

A successful pregnancy in a patient with secondary hypertension caused by adrenal adenoma: a case report

Background

Secondary hypertension is a rare complication in pregnancy that causes poor outcomes, such as preeclampsia, premature delivery, intrauterine growth retardation, stillbirths, spontaneous abortion or intrauterine death. Cushing’s disease caused by an adrenal adenoma is rare during pregnancy and may be overlooked by obstetricians and physicians, but can lead to hypertension, diabetes mellitus and an increased risk of fetal and maternal morbidity. Approximately 200 cases have been reported in the literature. Here, we report the successful management of a pregnant patient with Cushing’s syndrome due to an adrenal adenoma.

Case presentation

The 35-year-old Chinese female had no individual or family medical history of hypertension, and did not exhibit chronic kidney disease, diabetes mellitus, autoimmune and common endocrine diseases. Her blood pressure was elevated from the 16th week of gestation and was not controlled by 30 mg nifedipine twice a day. Examination in our department revealed her 24 h urinary free cortisol (24 h UFC) level was 1684.3 μg/24 h (normal range: 20.26–127.55 μg/24 h) and plasma adrenocorticotropic hormone was < 1.00 ng/L in three independent measurements (normal range: 5–78 ng/L). Ultrasonography demonstrated a mass (2.9 cm × 2.8 cm) in the right side of the adrenal gland. Magnetic resonance imaging without contrast showed a 3.2 cm diameter mass in the right-side of the adrenal gland. Other medical tests were normal. Laparoscopic adrenalectomy was performed at the 26th week of gestation by a urological surgeon in the West China Hospital. Histopathology revealed an adrenocortical adenoma. After surgery, the patient accepted glucocorticoid replacement therapy. The remaining trimester continued without complication and her blood pressure was normal at the 32nd week of gestation without antihypertensive therapy. The patient gave birth to a healthy boy at the 40th week of gestation.

Conclusions

Cushing’s syndrome caused by adrenal adenoma is rare during pregnancy. This unique case suggested that analysis of the UFC level and circadian rhythm of plasma cortisol provides a suitable strategy to diagnose Cushing’s syndrome during pregnancy. Laparoscopic surgical resection in the second trimester provides a reasonable approach to treat pregnant patients exhibiting Cushing’s syndrome caused by an adrenal adenoma.

MANAGEMENT OF ENDOCRINE DISEASE: Management of Cushing's syndrome during pregnancy: solved and unsolved questions

With fewer than 200 reported cases, Cushing's syndrome (CS) in pregnancy remains a diagnostic and therapeutic challenge. In normal pregnancies, misleading signs may be observed such as striae or hypokalemia, while plasma cortisol and urinary free cortisol may rise up to 2- to 3-fold. While the dexamethasone suppression test is difficult to use, reference values for salivary cortisol appear valid. Apart from gestational hypertension, differential diagnosis includes pheochromocytoma and primary aldosteronism. The predominant cause is adrenal adenoma (sometimes without decreased ACTH), rather than Cushing's disease. There are considerable imaging pitfalls in Cushing's disease. Aberrant receptors may, in rare cases, lead to increased cortisol production during pregnancy in response to HCG, LHRH, glucagon, vasopressin or after a meal. Adrenocortical carcinoma (ACC) is rare and has poor prognosis. Active CS during pregnancy is associated with a high rate of maternal complications: hypertension or preeclampsia, diabetes, fractures; more rarely, cardiac failure, psychiatric disorders, infection and maternal death. Increased fetal morbidity includes prematurity, intrauterine growth retardation and less prevalently stillbirth, spontaneous abortion, intrauterine death and hypoadrenalism. Therapy is also challenging. Milder cases can be managed conservatively by controlling comorbidities. Pituitary or adrenal surgery should ideally be performed during the second trimester and patients should then be treated for adrenal insufficiency. Experience with anticortisolic drugs is limited. Metyrapone was found to allow control of hypercortisolism, with a risk of worsening hypertension. Cabergoline may be an alternative option. The use of other drugs is not advised because of potential teratogenicity and/or lack of information. Non-hormonal (mechanical) contraception is recommended until sustained biological remission is obtained.

Sociodemographic and Medical Risk Factors Associated With Antepartum Depression

Background

The increasing recognition of antenatal depression is an emerging area of concern in developing countries. We conducted a study to estimate the prevalence of antenatal mental distress and its relation with sociodemographic factors, obstetric factors, and physiological wellbeing in pregnant women attending public health facilities in Bengaluru, South India.

Methods

Nested within a cohort study, we assessed the mental status in 823 pregnant women in two public referral hospitals. Kessler Psychological Distress Scale (K-10 scale) was used to assess maternal depression. We collected information related to social-demographic characteristics and recent medical complaints. Descriptive statistics and odds ratios were calculated using SPSS version 20.

Results

Results show that 8.7% of the women exhibited symptoms of antenatal depression. Sociodemographic characteristics, such as respondent occupation, husband education, husband’s occupation, total family income showed significance. First time pregnancy, anemia, and high blood pressure were also associated with mental distress.

Conclusion

Our study has demonstrated feasibility of screening for mental health problems in public hospitals. Early detection of mental distress during pregnancy is crucial as it has a direct impact on the fetus. The public health facilities in low- and middle-income countries such as India should consider piloting and scaling up screening services for mental health conditions for pregnant women.

The plasma protein binding of the endogenous glucocorticosteroids is of vital importance for the concentrations in hair and saliva

BACKGROUND

The endogenous glucocorticosteroid cortisol (F) and its metabolite cortisone (E) are known to be involved in stress adaption and anti-inflammatory and immune regulatory effects. The ratios of F to E in the matrices serum, hair and saliva are different. The shift of this ratio by the enzyme activity of 11β-hydroxysteroid-dehydrogenase, which inactivates cortisol, was often discussed. The aim of our study was to calculate the contribution of the plasma protein binding (PPB) to this shift. The PPB of F is known to be 96% of the total F-Concentration in serum. The PPB of E was not analyzed in previous studies.

METHODS

Our study was designed to evaluate the correlation of corticosteroid concentrations in serum (total and free), hair and saliva. The samples were self-collected by the author (A.K.) monthly over a pregnancy cycle (1st samples before pregnancy, 8 samples during pregnancy and 5 samples postpartum). Serum protein binding was calculated from the determination of the total hormone concentrations of F and E (protein bound and unbound) and the free hormone concentrations in serum. The samples were processed by ether extraction and ultrafiltration. Hair samples were extracted with methanol and purified by solid-phase extraction. Saliva samples were collected using Salivette^® collection system. The concentrations of F and E were measured by liquid chromatography-mass spectrometry with LODs for free serum, total serum, hair and saliva of F: 0.11ng/mL, 2.13ng/mL, 1.6pg/mg, 0.08ng/mL and E: 0.12ng/mL, 0.54ng/mL, 2.1pg/mg, 0.09ng/mL, respectively.

RESULTS AND DISCUSSION

The serum concentrations (free and total) of both glucocorticosteroids rise up continuously during the time of pregnancy and decrease after delivery. The free and total serum concentrations were well correlated. No change was detected for the intensity of PPB of F. In contrast, the PPB of E decreases from 86.3% to 80.7% during pregnancy. The concentration ratios of F to E change from 3:1 in total serum to 1:1 in free serum. For hair samples, an increase of F and E in proximal segments was confirmed with the highest concentration 6.5weeks postpartum. Independently, corticosteroid concentrations in corresponding hair segments were found to be reduced with increasing distance from the root; an average decline of F and E by half in 5 and 6months was estimated, respectively. The counter effect of the mechanisms incorporation and wash-out is clearly visible. For saliva samples a good correlation with free, non-protein bound serum concentration was detected.

Update on adrenal insufficiency: diagnosis and management in pregnancy

PURPOSE OF REVIEW

Adrenal insufficiency in pregnancy, although relatively rare, has significant clinical implications on both maternal and fetal outcomes. Hypothalamo-pituitary-adrenal axis dynamics and physiological changes are complex, thus diagnosis and management of adrenal insufficiency in pregnancy remain challenging.

RECENT FINDINGS

Studies consistently demonstrate a rise in total serum cortisol with pregnancy, but less data are available on free cortisol levels. Salivary cortisol values have been measured in normal pregnancy and in a few studies using healthy nonpregnant women controls. Although this adds to our current knowledge of hypothalamo-pituitary-adrenal axis changes in pregnancy, clear-cut cortisol reference ranges are yet to be established. Serum cortisol and the cosyntropin stimulation test (albeit with higher peak cortisol thresholds) are currently the diagnostic tests of choice. Hydrocortisone is the preferred glucocorticoid replacement in pregnancy as it is inactivated by placental 11-β-hydroxysteroid dehydrogenase 2; dose titration may be required, but should be individualized depending on clinical course and mode of delivery.

SUMMARY

Further studies on the long-term effects of maternal glucocorticoid regimens on the fetus and potential modulators of fetal glucocorticoid sensitivity and placental 11-β-hydroxysteroid dehydrogenase 2 are needed and will be useful in guiding clinical management strategies in pregnant women with adrenal insufficiency.

Differential Effects of Estrogen on Corticosteroid-Binding Globulin Forms Suggests Reduced Cleavage in Pregnancy

Corticosteroid-binding globulin (CBG) is secreted as high-affinity CBG (haCBG), which may be cleaved by tissue proteases to low-affinity CBG (laCBG), releasing free cortisol. Pregnancy and the estrogen-based combined oral contraceptive pill (COCP) increase CBG concentrations twofold to threefold. The relative effects of these two hyperestrogenic states on the CBG affinity forms are unknown. We performed an observational study in 30 pregnant women, 27 COCP takers and 23 controls. We analyzed circulating total CBG, haCBG, laCBG, and free and total cortisol concentrations. In pregnancy, total CBG and haCBG were increased compared to controls (both P < 0.0001); however, laCBG concentrations were similar. In COCP takers, total CBG and haCBG were increased [802 ± 41 vs compared to controls (both P < 0.0001)], but laCBG was also increased (P = 0.03). Pregnancy and use of COCP were associated with a comparable rise in haCBG, but laCBG was lower in pregnancy (P < 0.0001). These results were consistent with an estrogen-mediated increase in CBG synthesis in both hyperestrogenemic states but with reduced CBG cleavage in pregnancy relative to the COCP, perhaps due to pregnancy-induced CBG glycosylation. Speculatively, increased circulating haCBG concentrations in pregnancy may provide an increased reservoir of CBG-bound cortisol to prepare for the risk of puerperal infection or allow for cortisol binding in the face of competition from increased circulating progesterone concentrations.

Hippocampal learning, memory, and neurogenesis: Effects of sex and estrogens across the lifespan in adults

This article is part of a Special Issue "Estradiol and Cognition". There are sex differences in hippocampus-dependent cognition and neurogenesis suggesting that sex hormones are involved. Estrogens modulate certain forms of spatial and contextual memory and neurogenesis in the adult female rodent, and to a lesser extent male, hippocampus. This review focuses on the effects of sex and estrogens on hippocampal learning, memory, and neurogenesis in the young and aged adult rodent. We discuss how factors such as the type of estrogen, duration and dose of treatment, timing of treatment, and type of memory influence the effects of estrogens on cognition and neurogenesis. We also address how reproductive experience (pregnancy and mothering) and aging interact with estrogens to modulate hippocampal cognition and neurogenesis in females. Given the evidence that adult hippocampal neurogenesis plays a role in long-term spatial memory and pattern separation, we also discuss the functional implications of regulating neurogenesis in the hippocampus.

Effects of season, age, sex, and housing on salivary cortisol concentrations in horses

Analysis of salivary cortisol is increasingly used to assess stress responses in horses. Because spontaneous or experimentally induced increases in cortisol concentrations are often relatively small for stress studies, proper controls are needed. This requires an understanding of the factors affecting salivary cortisol over longer times. In this study, we have analyzed salivary cortisol concentration for 6 mo in horses (n = 94) differing in age, sex, reproductive state, and housing. Salivary cortisol followed a diurnal rhythm with the highest concentrations in the morning and a decrease throughout the day (P < 0.001). This rhythm was disrupted in individual groups on individual days; however, alterations remained within the range of diurnal changes. Comparison between months showed highest cortisol concentrations in December (P < 0.001). Cortisol concentrations increased in breeding stallions during the breeding season (P < 0.001). No differences in salivary cortisol concentrations between nonpregnant mares with and without a corpus luteum existed. In stallions, mean daily salivary cortisol and plasma testosterone concentrations were weakly correlated (r = 0.251, P < 0.01). No differences in salivary cortisol between female and male young horses and no consistent differences between horses of different age existed. Group housing and individual stabling did not affect salivary cortisol. In conclusion, salivary cortisol concentrations in horses follow a diurnal rhythm and are increased in active breeding sires. Time of the day and reproductive state of the horses are thus important for experiments that include analysis of cortisol in saliva.

Variation in maternal urinary cortisol profiles across the peri-conceptional period: a longitudinal description and evaluation of potential functions

STUDY QUESTION

How do women's first morning urinary cortisol levels, a marker of stress axis activity, vary during the peri-conceptional period (the 12 weeks around conception)?

SUMMARY ANSWER

First morning urinary cortisol follows an overall increasing trajectory across the peri-conceptional period, interrupted by 2 week-long decreases during the week preceding conception and the fifth week following conception.

WHAT IS KNOWN ALREADY

Later gestational stages (i.e. second and third trimesters) are characterized by increasing levels of circulating cortisol. This increase is hypothesized to constitute a response to the energy demands imposed by fetal growth, and the development of energy reserves in preparation for nursing and performing regular activities while carrying pregnancy's extra weight and volume.

STUDY DESIGN, SIZE, DURATION

This study is based on a data set collected as part of a longitudinal, naturalistic investigation into the interactions between the stress (hypothalamic-pituitary-adrenal axis (HPAA)) and reproductive (hypothalamic-pituitary-gonadal axis (HPGA)) axes. Biomarkers of HPAA and HPGA function were quantified in first morning urinary specimens collected every other day from 22 healthy women who conceived a pregnancy during the study. We analyzed the longitudinal within- and between-individual variation in first morning urinary cortisol levels across the 12-week peri-conceptional period.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Participants were recruited from two rural, aboriginal, neighboring communities in Guatemala. Cortisol, estradiol and progesterone metabolites (estrone-3-glucuronide and pregnanediol glucuronide, respectively) and hCG levels were quantified in first morning urinary specimens using immunoassays to determine time of conception and confirm pregnancy maintenance. Linear mixed-effects models with regression splines were used to evaluate the magnitude and significance of changes in cortisol trajectories.

MAIN RESULTS AND THE ROLE OF CHANCE

Overall, maternal first morning urinary cortisol increased from 6 weeks prior to conception (geometric mean ± SD = 58.14 ± 36.00 ng/ml) to 6 weeks post-conception (89.29 ± 46.76 ng/ml). The magnitude of the increase between the pre- and post-conception periods varied significantly between women (likelihood ratio test statistic = 8.0017, P = 0.005). The peri-conceptional period is characterized by an increasing cortisol trajectory (+1.36% per day; P = 0.007) interrupted by a week-long decline immediately prior to conception (-4.02% per day; P = 0.0013). After conception cortisol increased again (+1.73% per day; P = 0.0008) for 4 weeks, fell in the fifth week (-6.60% per day; P = 0.0002) and increased again in post-conceptional week 6 (+8.86% per day; P = 0.002). Maternal urinary cortisol levels varied with sex of the gestating embryo. During gestational week 2, mothers carrying female embryos (N = 10) had higher mean cortisol levels than those carrying male embryos (N = 9) (t(17) = 2.28, P = 0.04).

LIMITATIONS, REASONS FOR CAUTION

Our results are based on a relatively small sample (n = 22) of women. However, our repeated-measures design with an average of 27 ± 8 (mean ± SD) data points per woman strengthens the precision of estimates resulting in high statistical power. Additionally, our study population's high degree of ethnic and cultural homogeneity reduces the effects of confounders compared with those found in industrialized populations. This higher level of homogeneity also increases our statistical power. However, since there may be small differences in absolute cortisol values among ethnic groups, the social and biological background of our sample may affect the generalizability of our results. General patterns of HPAA activity, however, are expected to be universal across women. Finally, as there is, to the best of our knowledge, no evidence to the contrary, we assumed that urinary cortisol levels reflect HPAA activity and that changes in gonadal steroids across the menstrual cycle do not affect the levels of free cortisol measured in urine.

WIDER IMPLICATIONS OF THE FINDINGS

To our knowledge, this is the first longitudinal profile of basal maternal HPAA activity across the peri-conceptional period. A basic understanding of the normative (basal as opposed to stress-induced) changes in HPAA activity across this period is needed to accurately assess women's stress at this juncture. Importantly, changes in HPAA activity are likely to play a critical role in ovulation, fertilization, implantation, placentation and embryonic programing. Thus, this novel information should aid in the development of interventions aimed at preventing or moderating undesired effects of maternal physiological stress during the peri-conceptional period on reproductive outcomes as well as embryonic development.

STUDY FUNDING/COMPETING INTERESTS

This research was funded by a CIHR IGH Open Operating grant (CIHR 106705) to P.A.N. and L.Z.; a Simon Fraser University (SFU) President's Start-up grant, a Community Trust Endowment Fund grant through SFU's Human Evolutionary Studies Program and a Michael Smith Foundation for Health Research Career Investigator Scholar Award to P.A.N.; an NSERC Discovery grant to L.Z.; a CIHR Post-Doctoral Fellowship to C.K.B. and an NSERC Undergraduate Student Research Award to H.M. and J.C.B. The funding agencies had no role in the design, analysis, interpretation or reporting of the findings. There are no competing interests.

TRIAL REGISTRATION NUMBER

Not applicable.

Expression microarray identifies the unliganded glucocorticoid receptor as a regulator of gene expression in mammary epithelial cells

Background

While glucocorticoids and the liganded glucocorticoid receptor (GR) have a well-established role in the maintenance of differentiation and suppression of apoptosis in breast tissue, the involvement of unliganded GR in cellular processes is less clear. Our previous studies implicated unliganded GR as a positive regulator of the BRCA1 tumour suppressor gene in the absence of glucocorticoid hormone, which suggested it could play a similar role in the regulation of other genes.

Methods

An shRNA vector directed against GR was used to create mouse mammary cell lines with depleted endogenous levels of this receptor in order to further characterize the role of GR in breast cells. An expression microarray screen for targets of unliganded GR was performed using our GR-depleted cell lines maintained in the absence of glucocorticoids. Candidate genes positively regulated by unliganded GR were identified, classified by Gene Ontology and Ingenuity Pathway Analysis, and validated using quantitative real-time reverse transcriptase PCR. Chromatin immunoprecipitation and dual luciferase expression assays were conducted to further investigate the mechanism through which unliganded GR regulates these genes.

Results

Expression microarray analysis revealed 260 targets negatively regulated and 343 targets positively regulated by unliganded GR. A number of the positively regulated targets were involved in pro-apoptotic networks, possibly opposing the activity of liganded GR targets. Validation and further analysis of five candidates from the microarray indicated that two of these, Hsd11b1 and Ch25h, were regulated by unliganded GR in a manner similar to Brca1 during glucocorticoid treatment. Furthermore, GR was shown to interact directly with and upregulate the Ch25h promoter in the absence, but not the presence, of hydrocortisone (HC), confirming our previously described model of gene regulation by unliganded GR.

Conclusion

This work presents the first identification of targets of unliganded GR. We propose that the balance between targets of liganded and unliganded GR signaling is responsible for controlling differentiation and apoptosis, respectively, and suggest that gene regulation by unliganded GR may represent a mechanism for reducing the risk of breast tumourigenesis by the elimination of abnormal cells.

Glucocorticoid receptor gene polymorphisms and disease activity during pregnancy and the postpartum period in rheumatoid arthritis

INTRODUCTION

The mechanism underlying the spontaneous improvement of rheumatoid arthritis (RA) during pregnancy and the subsequent postpartum flare is incompletely understood, and the disease course varies widely between pregnant RA patients. In pregnancy, total and free levels of cortisol increase gradually, followed by a postpartum decrease to prepregnancy values. The glucocorticoid receptor (GR) polymorphisms BclI and N363S are associated with relatively increased glucocorticoid (GC) sensitivity, whereas the 9β and ER22/23EK polymorphisms of the GR gene are associated with a relatively decreased GC sensitivity. We examined the relation between the presence of these GR polymorphisms and level of disease activity and disease course of RA during pregnancy and postpartum.

METHODS

We studied 147 participants of the PARA study (Pregnancy-Induced Amelioration of Rheumatoid Arthritis study), a prospective study investigating the natural improvement during pregnancy and the postpartum flare in women with RA. Patients were visited, preferably before pregnancy, at each trimester and at three postpartum time points. On all occasions, disease activity was scored by using DAS28. All patients were genotyped for the GR polymorphisms BclI, N363S, 9β, and ER22/23EK and divided in groups harboring either polymorphisms conferring increased GC sensitivity (BclI and N363S; GC-S patients) or polymorphisms conferring decreased GC sensitivity (9β or 9β + ER22/23EK; GC-I patients). Data were analyzed by using a mixed linear model, comparing GC-S patients with GC-I patients with respect to improvement during pregnancy and the postpartum flare. The cumulative disease activity was calculated by using time-integrated values (area under the curve, AUC) of DAS28 in GC-I patients versus GC-S patients. Separate analyses were performed according to the state of GC use.

RESULTS

GC-S patients treated with GC had a significantly lower AUC of DAS28 in the postpartum period than did GC-I patients. This difference was not observed in patients who were not treated with GCs. During pregnancy, GC-S and GC-I patients had comparable levels of disease activity and course of disease.

CONCLUSIONS

Differences in relative GC sensitivity, as determined by GR polymorphisms, are associated with the level of disease activity in the postpartum period in GC-treated patients, but they do not seem to influence the course of the disease per se.

Cortisol and progestin release, heart rate and heart rate variability in the pregnant and postpartum mare, fetus and newborn foal

The mechanisms leading to parturition in the horse in many aspects differ from those in other species. Pregnancy is maintained not by progesterone but by 5α-pregnanes and the progestin precursor pregnenolone originates from the fetus. As parturition approaches, the fetal adrenal switches from pregnenolone to cortisol synthesis but it is not known whether cortisol crosses the placenta. We hypothesized that in parallel to fetal cortisol release, cortisol in the maternal circulation increases before foaling and this increase can be determined in both saliva and plasma. In addition, maternal, fetal and neonatal heart rate and heart rate variability were measured. In 25 pregnant mares, saliva for cortisol analysis was collected 4 times daily from 15 days before to 5 days after foaling. In 13 mares, in addition, fetomaternal electrocardiogram (ECG) recordings were made and blood samples for progestin and cortisol analysis were collected once daily. Heart rate (HR) was recorded until 5 days after foaling. The heart rate variability (HRV) variables standard deviation of the beat-to-beat (RR) interval (SDRR) and root mean square of successive RR differences (RMSSD) were calculated. From Days 15 to 4 before parturition, progestin concentration increased (peak 267 ± 42 ng/mL) and decreased thereafter (P < 0.05, day of foaling 113 ± 18 ng/mL). A prepartum increase in maternal cortisol concentrations was evident in blood (P < 0.05) and saliva (P < 0.05) and paralleled the decrease in progestin concentrations. In mares, HR remained constant during the last days of pregnancy but decreased within one day after parturition (P < 0.05) while maternal HRV did not change. In the fetus and neonate, HR increased from before to after birth (P < 0.05) indicating increasing demands on the cardiovascular system with adaptation to extrauterine life.

Longitudinal study of the renin angiotensin aldosterone system in purebred Spanish broodmares during pregnancy

During pregnancy, the coordinated interaction of the components of the renin-angiotensin-aldosterone system (RAAS) plays a vital role in accommodating the cardiovascular, haemodynamic and haematological needs imposed by foetal development and the placenta. This significantly influences the birth weight of the neonate and foetal viability. Although the evolution of each of the components of this system has been widely described in various species, it has not yet been clarified in the mare. Thus, the objectives of the present research were: 1) to establish reference values for renin (REN), angiotensin II (ANG-II) and aldosterone (ALD) concentrations in Spanish broodmares, and 2) to analyse the evolution of the aforementioned components during pregnancy. Thirty-one Purebred Spanish broodmares aged between 5 and 15 years old were studied for 11 months of pregnancy and compared to a control group composed of 11 non-pregnant Spanish mares. Morning venous blood samples were drawn on a monthly basis during pregnancy and pre-treated to prevent degradation until subsequent analysis. Serum REN, ANG-II and ALD concentrations were analysed by competitive immunoassay. This study found that pregnancy in Purebred Spanish broodmares is characterised by a gradual increase in REN concentrations, variable fluctuations in ALD concentrations, and no significant modifications in ANG-II concentrations. These results could provide potentially valuable information in understanding the physiological basis of the RAAS in mares, since we have been able to establish specific reference ranges for these components, as well as obtaining information on their evolution during pregnancy. As is often the case in other animal species, the increase in RAAS activity is a natural physiological process that occurs during pregnancy in Spanish broodmares. This may also be related to certain metabolic and hormone responses that contribute to the control of homeostasis in pregnant mares.

Measuring cortisol in human psychobiological studies

The steroid cortisol is an extensively studied and important variable in developmental and other behavioral studies. Cortisol has been assayed by various methods using a range of substrates including blood, saliva, and urine. Cortisol in blood exists in two forms. While most is bound to carrier proteins, a small portion exists in a soluble free form. The informed choice of cortisol fraction and measurement method is critical for research. Such choices should be influenced by understanding the characteristics of the various cortisol fractions, along with their binding proteins' biological functions and relationship to the hypothalamic-pituitary-adrenal (HPA) axis. The goal of this paper is to familiarize researchers with key points for evaluating the choice of total and free cortisol in research as well reviewing various options for measuring free cortisol. These points are raised with special emphasis on their significance during pregnancy and the post-partum. Such information may prove useful in informing researcher's cortisol-related protocols and in the interpretation of cortisol data.

Maternal and fetal hypothalamic-pituitary-adrenal axes during pregnancy and postpartum

The principal modulators of the hypothalamic-pituitary-adrenal (HPA) axis are corticotropin-releasing hormone (CRH) and arginine-vasopressin (AVP). Corticotropin-releasing hormone is not exclusively produced in the hypothalamus. Its presence has been demonstrated at peripheral inflammatory sites. Ovulation and luteolysis bear characteristics of an aseptic inflammation. CRH was found in the theca and stromal cells as well as in cells of the corpora lutea of human and rat ovaries. The cytoplasm of the glandular epithelial cells of the endometrium has been shown to contain CRH and the myometrium contains specific CRH receptors. It has been suggested that CRH of fetal and maternal origin regulates FasL production, thus affecting the invasion (implantation) process through a local auto-paracrine regulatory loop involving the cytotrophoblast cells. Thus, the latter may regulate their own apoptosis. During pregnancy, the plasma level of circulating maternal immunoreactive CRH increases exponentially from the first trimester of gestation due to the CRH production in the placenta, decidua, and fetal membranes. The presence in plasma and amniotic fluid of a CRH-binding protein (CRHbp) that reduces the bioactivity of circulating CRH by binding is unique to humans. Maternal pituitary ACTH secretion and plasma ACTH levels rise during pregnancy-though remaining within normal limits-paralleling the rise of plasma cortisol levels. The maternal adrenal glands during pregnancy gradually become hypertrophic. Pregnancy is a transient, but physiologic, period of hypercortisolism. The diurnal variation of plasma cortisol levels is maintained in pregnancy, probably due to the secretion of AVP from the parvicellular paraventricular nuclei. CRH is detected in the fetal hypothalamus as early as the 12th week of gestation. CRH levels in fetal plasma are 50% less than in maternal plasma. The circulating fetal CRH is almost exclusively of placental origin. The placenta secretes CRH at a slower rate in the fetal compartment. AVP is detected in some neurons of the fetal hypothalamus together with CRH. AVP is usually detectable in the human fetal neurohypophysis at 11 to 12 weeks gestation and increases over 1000-fold over the next 12 to 16 weeks. The role of fetal AVP is unclear. Labor appears to be a stimulus for AVP release by the fetus. The processing of POMC differs in the anterior and intermediate lobes of the fetal pituitary gland. Corticotropin (ACTH) is detectable by radioimmunoassay in fetal plasma at 12 weeks gestation. Concentrations are higher before 34 weeks gestation, with a significant fall in late gestation. The human fetal adrenal is enormous relative to that of the adult organ. Adrenal steroid synthesis is increased in the fetus. The major steroid produced by the fetal adrenal zone is sulfoconjugated dehydroepiandrosterone (DHEAS). The majority of cortisol present in the fetal circulation appears to be of maternal origin, at least in the nonhuman primate. The fetal adrenal uses the large amounts of progesterone supplied by the placenta to make cortisol. Another source of cortisol for the fetus is the amniotic fluid where cortisol converted from cortisone by the choriodecidua, is found. In humans, maternal plasma CRH, ACTH, and cortisol levels increase during normal labor and drop at about four days postpartum; however, maternal ACTH and cortisol levels at this stage are not correlated. In sheep, placental CRH stimulates the fetal production of ACTH, which in turn leads to a surge of fetal cortisol secretion that precipitates parturition. The 10-day-long intravenous administration of antalarmin, a CRH receptor antagonist, significantly prolonged gestation compared to the control group of animals. Thus, CRH receptor antagonism in the fetus can also delay parturition. The HPA axis during the postpartum period gradually recovers from its activated state during pregnancy. The adrenals are mildly suppressed in a way analogous to postcure Cushing's syndrome. Provocation testing has shown that hypothalamic CRH secretion is transiently suppriently suppressed at three and six weeks postpartum, normalizing at 12 weeks.

Pregnant women become insensitive to cold stress

BACKGROUND: The function of the hypothalamic-pituitary-adrenal (HPA) axis is known to be altered during pregnancy, but it has not been tested with a natural stressor. METHODS: A group of pregnant women (n = 10) were tested towards the end of pregnancy (mean 36.8 PlusMinus; 2.5 weeks gestation) and about 8 weeks postpartum (mean 7.8 PlusMinus; 1.5 weeks), together with a matched control group, with a one minute cold hand stressor test. Saliva samples were collected before and 10 and 20 minutes after the test, and stored for later radioimmunoassay of cortisol. RESULTS: The control group showed a highly significant response to the test. The pregnant group showed no response, and the postpartum group a variable but non significant one CONCLUSIONS: This shows that the HPA axis becomes hypofunctional to a natural stressor at the end of pregnancy. It is suggested that one possible evolutionary function for this is to protect the fetus from the stress responses of the mother.

Hormonal alterations in rheumatoid arthritis, including the effects of pregnancy

A number of hormonal abnormalities are present in RA patients. A major theme of these abnormalities seems to be that deficiencies in the production or action of gonadal (estrogens and androgens) and adrenal (corticosteroids and DHEA) hormones may be involved in regulating the onset, severity, and progression of RA. Differences in RA incidence and activity in the pregnant and postpartum periods provide the strongest support for this view. Hormonal changes during these periods clearly have the potential to exert profound effects on RA incidence and activity. The effect of pregnancy on RA activity is actually greater than the effect of some of the newer therapeutic agents. The striking increase in corticosteroids, estrogen, and progesterone during pregnancy may suppress RA onset or activity through the regulation of production or action of cytokines such as TNF alpha, IL-1, IL-6, IL-12, and IL-10. The relative adrenal- and gonadal-deficient environment of the postpartum period further supports the view that hormonal deficiencies predispose to the development or increased activity of RA. These observations justify the search for hormonal abnormalities in RA patients outside the pregnancy and postpartum periods. In particular, further studies on the period before the onset of disease are needed. Additional evidence does exist that a functional abnormality in the adrenal glands in RA patients results in dysregulation of corticosteroid and DHEA production. These abnormalities seem to be linked to aging and disease activity. It is still not established whether these abnormalities are primary or secondary, although data indicating adrenal hypofunction before the development of RA or within the first year of disease activity suggest a primary abnormality. Several hormonal abnormalities seem to be restricted by gender and age, particularly around perimenopause and menopause. These age- and gender-influenced effects may be the cause of some of the contradictory data reviewed here. Studies in the future should make greater efforts to segregate study populations by age, gender, and reproductive status. The identification of the specific hormonal abnormalities and patient populations that are at risk is important, because these factors may allow new therapeutic approaches that are less toxic than current regimens.

Maternal hypothalamic-pituitary-adrenal axis in pregnancy and the postpartum period. Postpartum-related disorders

During pregnancy, placenta-derived CRH increases exponentially in the plasma. Circulating levels of CRH-binding protein decrease considerably in the last trimester of pregnancy, resulting in further elevation of bioavailable plasma CRH. The adrenal glands during pregnancy gradually become hypertrophic because of the increase in ACTH, which parallels that of CRH. Thus, pregnancy is a transient period of relative hypercortisolism. The activation of the hypothalamic-pituitary-adrenal axis during pregnancy has been proposed to function as a biological clock. In this model, the placenta is perceived as a stress-sensitive organ and placental CRH as a timing starter, determining a preterm, term, or postterm labor. During pregnancy, as well as during the immediate postpartum period, the hypothalamic maternal CRH secretion is suppressed, because of the circulating levels of cortisol. Hypothalamic CRH secretion normalizes within 12 weeks. This transient postpartum maternal hypothalamic CRH suppression, together with the steroid withdrawal that follows parturition, might be causally related to the mood disorders and the vulnerability to autoimmune diseases such as thyroiditis or rheumatoid arthritis often observed during the postpartum period.

Corticotropin-releasing hormone and cortisol: longitudinal associations with depression and antisocial behavior in pregnant adolescents

OBJECTIVE

To examine the concurrent and longitudinal associations between corticotropin-releasing hormone (CRH) and cortisol concentrations and depression and antisocial behavior (conduct disorder symptoms) in pregnant adolescents.

METHOD

Fifty-nine adolescents were evaluated in early pregnancy (9-21 weeks' gestation), late pregnancy (32-34 weeks' gestation), and the postpartum period (4-5 weeks postpartum). Symptoms of depression and conduct disorder were obtained from the Diagnostic Interview Schedule for Children.

RESULTS

Lower concentrations of CRH were related to a greater number of depression symptoms in early pregnancy (p < .05) and in late pregnancy (p < .05). Lower concentrations of CRH also were related to a greater number of conduct disorder symptoms in early pregnancy (p < .06) and in the postpartum period (p < .05).

CONCLUSION

The findings support the long-standing hypothesis that stress-related products of the hypothalamic-pituitary-adrenal axis are associated with emotions and behavior during pregnancy.

High precursor level in maternal blood results from the alternate mode of proopiomelanocortin processing in human placenta

OBJECTIVE

ACTH-producing non-pituitary tumours are often associated with altered precursor processing, particularly in the most aggressive ones. Since placental tissue is characterized by its ability to express the proopiomelanocortin (POMC) gene and rapid cellular proliferation, we examined whether intact POMC could be released physiologically during human gestation.

SUBJECTS

One hundred and fifty six normal pregnant women, 12 with multiple pregnancies, and 23 non-pregnant controls. Twenty-eight women were studied in the immediate postpartum period.

MEASUREMENTS

We measured plasma POMC levels with a specific immunoradiometric assay (IRMA) using a combination of antibodies directed against ACTH and beta endorphin. Results obtained with this first IRMA were confirmed in 22 subjects with a second assay using the same beta endorphin antibody and a more distal antibody directed against the N-terminal fragment of POMC. Reverse transcription-PCR detected full length, pituitary-like, POMC mRNA in human placenta.

RESULTS

Plasma POMC was undetectable (< 60 U/ml) in 23 normal subjects. In normal monofetal pregnancies, POMC became detectable in most women by the third month and then increased steadily until midgestation: 168 +/- 108 (U/ml; mean +/- SD) between 12 and 15 weeks, 190 +/- 103 between 16 and 19 weeks, 324 +/- 180 between 20 and 23 weeks, 276 +/- 171 between 24 and 27 weeks, 292 +/- 177 between 28 and 31 weeks, 290 +/- 235 between 32 and 35 weeks and 308 +/- 210 between 36 weeks and parturition. Plasma POMC was significantly higher in multiple pregnancies with very high levels in three triplet-bearing mothers: 671, 941, and 1731 U/ml at 31, 33 and 32 weeks, respectively. POMC levels felt quickly in post partum, becoming undetectable in five of 13 women on day 1, seven of eight on day 2 and five of six on day 3. Plasma POMC displayed no diurnal variation, was not suppressed by glucocorticoid administration and did not correlate with plasma ACTH or cortisol. In contrast, plasma POMC positively correlated with plasma CRH.

CONCLUSIONS

Pregnancy is the only condition in which POMC is produced and released physiologically, similar in some respects to the ectopic ACTH syndrome. POMC is derived solely from the placenta, with no interference from maternal pituitary secretion, and is thus a new and specific placental marker.

The hypothalamic-pituitary-adrenal axis and the female reproductive system

The hypothalamic-pituitary-adrenal (HPA) axis and the female reproductive system are intertwined and exhibit a complex relationship. Thus, the HPA axis exerts profound, mostly inhibitory effects, on the reproductive axis, with corticotropin-releasing hormone (CRH) and CRH-induced propiomelanocortin peptides inhibiting hypothalamic GnRH secretion, and with glucocorticoids inhibiting pituitary LH and ovarian estrogen and progesterone secretion and rendering estrogen-target tissues, such as the endometrium, resistant to the gonadal steroid. These effects of the HPA axis are responsible for the "hypothalamic" amenorrhea of stress, depression and eating disorders, and the hypogonadism of Cushing's syndrome. Conversely, estrogen directly stimulates the CRH gene, which may explain the slight hypercortisolism of females and the preponderance of depressive, anxiety, and eating disorders, as well as Cushing's disease in women. Interestingly, several components of the HPA axis and their receptors are present in reproductive tissues, as autocoid regulators of their various functions. These include ovarian and endometrial CRH, which may participate in the inflammatory processes of the ovary, that is, ovulation and luteolysis, and of the endometrium, that is, implantation and menstruation. Finally, the hypercortisolism of the latter half of pregnancy can be explained by high levels of placenta CRH in plasma. This hypercortisolism causes a transient adrenal suppression in the postpartum period, which may explain the postpartum blues/depression and autoimmune phenomena of this period.

Hormonal and pregnancy relationships to rheumatoid arthritis: convergent effects with immunologic and microvascular systems

OBJECTIVE

To review sex hormones and rheumatoid arthritis (RA) and the interrelationships between hormonal, immunological, and vascular systems.

DATA SOURCES

Publications detailing serum sex hormone levels and their HLA interactions, steroidogenesis, pregnancy, and therapeutic uses of sex hormones in RA.

STUDY SELECTION

Controlled studies of sex hormone levels in RA patients not previously treated with glucocorticoids.

DATA EXTRACTION

Mean (+/- SD) serum levels of dehydroepiandrosterone sulfate (DHEAS), testosterone (T), and estradiol (E2).

DATA SYNTHESIS

Mean (+/- SD) levels were collated into tables for women with pre-versus postmenopausal onsets of disease and men. Data were also ordered across all study groups by increasing mean levels of the control subjects. Pooled data were summarized statistically, and major sources of variation between the studies were identified.

CONCLUSIONS

Serum DHEAS, an adrenal androgen, was impressively decreased among women with premenopausal onset of RA. One study showed such deficiency years before disease onset. Serum T was somewhat decreased in the premenopausal onset group, but could be explained by decreased peripheral conversion of the lower levels of adrenal androgens. Women with postmenopausal onset of RA had modestly decreased serum DHEAS levels overall, but no difference in serum T, compared with controls. Male RA cases had consistently decreased serum levels of T, but not of DHEAS. Serum E2 was comparable in all RA versus control groups. The complex biology of pregnancy was interpreted as an example of vital interactions between hormonal, immunological, and vascular systems, as they may relate to the physiopathology of RA. The major age, sex, and hereditable determinants of RA were compared within a composite table of estimated relative risks. Elucidation of the interacting risk factors offers promising avenues of research in this complex disease.

Disturbances in dexamethasone suppression test and lower availability of L-tryptophan and tyrosine in early puerperium and in women under contraceptive therapy

This study investigates the function of the hypothalamic-pituitary-adrenal (HPA)-axis and the availability of L-tryptophan and tyrosine to the brain in postpartum women and in women taking long-term oral contraceptives. To this end, we have measured the following parameters in 50 women (i.e. 9 normal controls, 10 women taking oral contraceptives, and 31 postpartum females): plasma cortisol, L-tryptophan, tyrosine and the amino acids (CAA) known to compete with them for transport through the blood-brain barrier. We have determined the effects of 1 mg of dexamethasone on the above-mentioned biological markers in postpartum females. Plasma cortisol and tyrosine were significantly higher and lower, respectively, in puerperium and in women under contraceptive therapy as opposed to normal controls. L-Tryptophan was significantly lower in postpartum females, whilst the L-tryptophan/CAA ratio did not differ across the three study groups. Postpartum females revealed a significant negative relationship between the availability of L-tryptophan to the brain and postpartum mood, as measured by Zung's Depression and Anxiety Scales and State Anxiety Inventory. Dexamethasone had a significant suppressive effect on L-tryptophan/CAA and tyrosine/CAA ratios, with cortisol nonsuppression appearing in 82% of the postpartum females.

Glucocorticoid receptors in lymphocytes in anorexia nervosa

OBJECTIVE

The aim was to explore the down-regulation of the glucocorticoid receptors during hypercortisolaemia in anorexia nervosa.

DESIGN

Urine and plasma samples were obtained for cortisol determination and blood lymphocytes were isolated for receptor binding studies.

PATIENTS

Sixteen anorexic patients, aged 16-27 years, with a mean +/- SEM body mass index of 14.2 +/- 2.0 (ranging from 11.1 to 17.4), and 15 normal women were studied. Six patients were reinvestigated after a significant weight gain.

MEASUREMENTS

The binding capacity and affinity of the glucocorticoid receptors were measured with dexamethasone as ligand on lymphocytes.

RESULTS

In patients, both total and free plasma cortisol concentrations were higher than in the normal women, as was their urinary free cortisol; the number of glucocorticoid receptors per cell (Ro) and the binding affinity (Kd) for dexamethasone were, however, not significantly different (Ro: 7687 +/- 1750 vs 7347 +/- 1285 sites/cell; Kd: 7.7 +/- 2.4 vs 7.4 +/- 1.7 nM at 24 degrees C). After weight gain (14 +/- 2 to 16 +/- 2 kg/m2), receptor numbers were 8421 +/- 2126 (pre) and 9011 +/- 500 (post) sites/cell, which are not significantly different (P greater than 0.2); the Kd was unchanged (9.3 +/- 2.6 vs 9.2 +/- 2.4 nM). CONCLUSIONS Hypercortisolaemia does not down-regulate the lymphocyte glucocorticoid receptors in anorexia nervosa and a post-receptor defect might be involved in peripheral tissue resistance to the effects of glucocorticoid hormones in undernutrition.

Diurnal salivary cortisol patterns during pregnancy and after delivery: relationship to plasma corticotrophin-releasing-hormone

The circadian rhythm of salivary cortisol was studied in 10 healthy women every 4 weeks throughout pregnancy. In addition, in 12 women the diurnal patterns of salivary cortisol, serum cortisol, plasma ACTH, plasma CRH and serum progesterone were analysed in late third trimester pregnancy and again 3-5 days after delivery. Salivary cortisol profiles exhibited a clear circadian rhythm during pregnancy with an increase in mean salivary cortisol from the 25th to 28th week onwards reaching concentrations in late pregnancy more than twice as high as in non-pregnant controls, rapidly returning to normal concentrations after delivery. The coefficient of variation of salivary cortisol profiles decreased in third trimester pregnancy due to a parallel upward shift of cortisol concentrations (40.2 +/- 3.4% vs 77.6 +/- 6.6% after delivery, P less than 0.01). A diurnal pattern was also found for plasma ACTH and serum cortisol before and after delivery with lower concentrations post-partum (P less than 0.01). In late pregnancy, progesterone concentrations were significantly higher in the evening (930 +/- 85 nmol/l vs 813 +/- 74 nmol/l at 0900 h, P less than 0.01) but showed no diurnal variation post-partum. Plasma CRH was significantly elevated in late third trimester pregnancy (1.22 +/- 0.23 micrograms/l at 0900 h) but showed no diurnal change (1.30 +/- 0.28 micrograms/l at 1900 h). Moreover, no correlation between the free cortisol increase in late pregnancy and plasma CRH was noted despite a wide range of CRH levels (0.13-3.60 micrograms/l). In contrast, a significant correlation was observed between the serum progesterone increase and the salivary cortisol increase in late pregnancy (r = 0.70, P less than 0.05). These findings demonstrate that placental CRH is not the only regulator of maternal ACTH and cortisol release. Instead, our study suggests that placental CRH has little influence on baseline maternal adrenocortical function in pregnancy. The elevated salivary cortisol levels in pregnancy may be explained by glucocorticoid resistance owing to the antiglucocorticoid action of high progesterone concentrations.

Cushing's syndrome and pregnancy

Pregnancy is a rare occurrence in women with Cushing's syndrome. Amenorrhea or oligomenorrhea occurs in about 75% of premenopausal women with Cushing's syndrome as a result of suppression of gonadotrophin secretion primarily by excess glucocorticoids. We have reviewed pregnancies in women with Cushing's syndrome (63 cases from the literature and four cases of our own). Since pregnant women without Cushing's syndrome develop some features of Cushing's syndrome, such as hypertension, hyperglycemia, and striae, a high index of clinical suspicion must be maintained to prevent delay in diagnosis. The physiologic changes in adrenocorticosteroid metabolism during pregnancy further complicate the diagnosis. Maternal and fetal risks increase markedly when pregnancy does occur in women with hypercortisolism. However, the wide spectrum of severity of the disease mandates an individualized approach to the therapy in each case.

Mood changes, obstetric experience and alterations in plasma cortisol, beta-endorphin and corticotrophin releasing hormone during pregnancy and the puerperium

The relationships between mood change, obstetric experience and alterations in plasma cortisol, beta-endorphin (beta-EP) and corticotrophin-releasing hormone (CRH) were examined in a prospective study of 97 primiparous Australian women. Psychological measures were administered between the 28th week of pregnancy and the 3rd postnatal month, including the Profile of Mood States (POMS) and the Montgomery Asberg Depressive Rating Scale (MADRS). Blood samples were collected for cortisol, beta-EP and CRH assay on most of these occasions and during labour. Factor analysis was used to identify key subsets of psychological variables for use in the subsequent analyses. 'Mood disturbance' and 'tiredness' factors peaked at 38 weeks' gestation, while 'difficulty falling asleep' was greatest around the time of birth. Cortisol, beta-EP and CRH concentrations rose significantly as pregnancy advanced and peaked at birth; plasma CRH correlated with plasma cortisol (r = 0.54) and beta-EP (r = 0.32). Women with the highest 'mood disturbance' and MADRS depression scores at 28 weeks' gestation received significantly more pain relief during labour. Those women whose mood deteriorated from 38 weeks' gestation to postnatal day 2 had larger falls in plasma beta-EP after delivery (p less than 0.01) than those women whose mood improved or remained constant. Women in this mood-deteriorated subgroup also had significantly higher MADRS depression scores at 3 months (p less than 0.01). Mild antenatal depression (MADRS greater than 13) occurred in 5.2% of women and mild postnatal depression in 4.7%. Overall, these data suggest a role for circulating CRH in the regulation of maternal cortisol secretion and significant relationships between maternal postnatal mood states and beta-EP and between antenatal mood states and obstetric events.

Placental corticotropin-releasing hormone may be a stimulator of maternal pituitary adrenocorticotropic hormone secretion in humans

To clarify the physiological role of placental corticotropin-releasing hormone (CRH), we measured plasma CRH, ACTH, and cortisol throughout pregnancy. Cerebrospinal fluid (CSF) CRH levels and ACTH responsiveness to synthetic CRH were also quantified in pregnant and nonpregnant women. Maternal plasma CRH levels, which increased progressively during pregnancy, correlated well with both ACTH and cortisol in early labor, delivery, and postpartum samples, and also with cortisol levels in samples before labor. CSF CRH levels in term pregnant women did not differ from those of nonpregnant women. CRH infusion that attained similar plasma CRH levels to those found in late pregnancy elicited significant ACTH release in vivo and regular CRH test provoked normal ACTH response during early pregnancy but no response during late pregnancy. We concluded that: (a) maternal pituitary-adrenal axis correlates well with plasma CRH levels, which are high enough to provoke ACTH release from maternal pituitary; (b) hypothalamic CRH secretion in term pregnant women is not exaggerated; and (c) maternal pituitary is responsive to synthetic CRH in early but not late pregnancy, suggesting that maternal pituitary-adrenal axis is already activated by high circulating CRH. Placental CRH may be an important stimulator of the maternal pituitary-adrenal axis during pregnancy.

Biologically active corticotropin-releasing hormone in maternal and fetal plasma during pregnancy

Corticotropin-releasing hormone was measured in the plasma of 110 pregnant women and in the umbilical cord plasma of 25 premature infants and 43 infants born at term. Mean maternal plasma corticotropin-releasing hormone was undetectable (less than 41 pg/ml) until mid-second trimester, rose to a mean of 204 +/- 24 pg/ml by 30 weeks' gestation, to 326 +/- 41 by 35 weeks, and then rose sharply near term, with a mean of 2930 pg/ml at 38 to 40 weeks' gestation. Sequential measurements in seven pregnant women confirmed that plasma corticotropin-releasing hormone rose in a predictable pattern, with a dramatic increase in the final weeks of pregnancy. There was little hour-to-hour variability in maternal plasma concentrations. Corticotropin-releasing hormone was also detectable in umbilical cord plasma; mean corticotropin-releasing hormone was 194 +/- 44 in the preterm infants and 150 +/- 19 in the term infants. The corticotropin-releasing hormone extracted from both the maternal and fetal circulation was biologically active in vitro and caused the dose-dependent release of adrenocorticotropic hormone and beta-endorphin from cultured rat anterior pituitary cells. A significant correlation was found between maternal plasma corticotropin-releasing hormone and cortisol levels the morning after betamethasone administration, a finding that supports a physiologic role for maternal plasma corticotropin-releasing hormone. We conclude that the placenta secretes large amounts of biologically active corticotropin-releasing hormone into both the maternal and fetal circulation during pregnancy. We demonstrate that this corticotropin-releasing hormone is secreted into the maternal plasma in a reproducible pattern during normal term pregnancy and suggest that sequential corticotropin-releasing hormone measurements may prove to be of clinical utility. In addition, placental corticotropin-releasing hormone may be an important modulator of the hypothalamic-pituitary-adrenal axis during pregnancy.

Plasma corticotrophin-releasing factor (CRF) in normal pregnancy

Corticotrophin-releasing factor (CRF) was measured directly in maternal plasma using an immunoradiometric assay (IRMA). In the first and second trimester CRF levels were within the non-pregnant range (mean 15 pg/ml). A total of 72 women was followed sequentially from 28 weeks until delivery and CRF levels rose from a median of 20 pg/ml at 28 weeks to 1320 pg/ml at 40 weeks and 1732 pg/ml during labour. There was a strong correlation (rs = 0.81, P less than 0.001) between gestational age and CRF levels. The rate of rise of CRF (pg/ml) per week was associated with weight gain (rs = 0.36, P less than 0.05) but with no other obstetric variable. There was an association between umbilical cord and maternal plasma CRF levels (rs = 0.54, P less than 0.01).

Plasma corticosteroid patterns in the fetus

In umbilical vein blood samples collected in 137 fetuses between 19 and 31 weeks of gestation, cortisol (F), cortisone (E), 17-hydroxyprogesterone (17-OHP) and 11-deoxycortisol (S) were radioimmunoassayed after column chromatography on Sephadex LH-20 of plasma extracts. While F levels plateaued throughout the period considered those of E displayed an increasing pattern which appeared to be comparable with that of unbound F in pregnant women. The declining pattern of S and more particularly of 17-OHP would suggest an increasing utilization and metabolization of these F precursors by the maturing fetus. E was not correlated with either 17-OHP or S but showed a significant correlation with F. S and 17-OHP were correlated with each other and with F. The significance of these correlations was discussed according to the different origin of these steroids and to their metabolic relationships. The application of this method for the prenatal diagnosis of inborn errors of steroid biogenesis is suggested.

Secretion of corticotropin-releasing hormone by superfused human placental fragments

Corticotropin-releasing hormone (CRH) immunoreactivity (IR) is present in the blood of women in the 3rd trimester of pregnancy and in placental extracts. We have used a placental fragment superfusion system to investigate the release of CRH from fresh placental tissue. Fragments of normal term placenta were mixed with Biogel P2, packed into minicolumns and superfused with carbogen-gassed Earles buffer at 37 degrees C. The rheology of the superfusion system was determined and the oxygen consumption of the superfused placental fragments indicated viability of the tissue preparation over a 5-hour time span. CRH IR in the eluate was measured by radioimmunoassay (RIA) using the 41 residue synthetic peptide human, rat CRH-41 (h, r CRH-41) as the standard, 125I labelled Tyr- h, r CRH as the tracer and rabbit anti-ovine CRH as the antibody. The sensitivity of the assay is 2 pM. Size exclusion chromatography on Sephadex G-50 of the placental column eluate displayed one major peak of CRH IR which co-eluted with that of h, r CRH. Placental fragment superfusate displayed potent CRH bioactivity as assessed by beta-endorphin secretion from ovine pituitary cells. Replacing the superfusing medium of the placental fragments with 45 mM KCl resulted in a prompt increase in the release of CRH IR. These results indicate that placental cells in vitro secrete a molecule of similar molecular weight, immunoreactivity and bioactivity to h, r CRH and that the rate of secretion may be regulated.

Human placenta and the hypothalamic-pituitary-adrenal axis

Maternal plasma bound and free cortisol rises during pregnancy, while maternal plasma IR-ACTH is initially low but soon rises inspite of the further increase of plasma free cortisol. This rise of plasma ACTH during pregnancy, can not be attributed to changes of plasma levels of estrogens or progesterone. It is possible that the human placenta is responsible for the rise in maternal plasma ACTH during pregnancy. There are two possible mechanisms by which this effect could occur: 1) by the placental secretion of CRH into the maternal circulation, which stimulates the maternal pituitary to secrete ACTH, and 2) the secretion of placental POMC-derived peptides. Recent data indicate that the human placenta is capable of both of these actions: A) The POMC and CRH genes are expressed in human placenta; B) the human term placenta is able to secrete both CRH and POMC-derived peptides in vitro; C) the CRH present in the plasma of pregnant women is bioactive and in sufficient levels to be effective on maternal pituitary; D) synthetic hCRH can stimulate the release of placental POMC peptides in vitro. We conclude that the human placenta may be a modulator of the HPA axis during pregnancy in a number of possible ways. Additional experimental work should clarify the intriguing interaction between the HPA axis and the human placenta during pregnancy, labor and delivery.

Clinical use of unbound plasma cortisol as calculated from total cortisol and corticosteroid-binding globulin

A method to calculate unbound cortisol from total cortisol (measured by competitive protein binding) and CBG (measured by radial immunodiffusion) based on the binding equilibrium has been evaluated. The calculated results (y) correlate well with those (x) obtained by centrifugal ultrafiltration at 37 degrees C (y = 1.04 x - 2.11 ng/ml; r = 0.975; n = 150). The concentration of CBG is similar in normal men (37.7 +/- 3.5 (SD) micrograms/ml; n = 12) and women (39.5 +/- 3.7 (SD) micrograms/ml; n = 7) and shows no diurnal variation, but marked diurnal variation is observed for total cortisol (193.7 +/- 35.0 (SD) ng/ml at 08.00 h vs 43.2 +/- 23.3 (SD) ng/ml at 22.00 h; n = 19) and particularly for unbound cortisol (16.5 +/- 5.6 (SD) ng/ml at 08.00 h vs 2.3 +/- 1.8 (SD) ng/ml at 22.00 h; n = 19). The concentration of CBG (89.1 +/- 11.2 (SD) micrograms/ml) and of total cortisol (395.6 +/- 103.3 (SD) ng/ml at 08.00 h; 110.3 +/- 16.6 (SD) ng/ml at 22.00 h) are clearly elevated in estrogen treated women (n = 11) but unbound cortisol levels (17.2 +/- 7.7 (SD) ng/ml at 08.00 h; 2.5 +/- 0.5 (SD) ng/ml at 22.00 h) are similar to the control group. The concentration of CBG is significantly decreased in patients with Cushing's syndrome (33.2 +/- 5.6 micrograms/ml; n = 17) and unbound cortisol is relatively more elevated than total cortisol in these patients. In adrenal insufficiently CBG is normal, but total and unbound cortisol are markedly decreased. There is a significant decrease of CBG in hyperthyroidism (35.7 +/- 5.5 micrograms/ml; n = 22), in cirrhosis (32.0 +/- 8.0 micrograms/ml; n = 14) and in renal disease and a significant increase in patients treated with antiepileptic drugs (47.5 +/- 6.3 micrograms/ml; n = 14), but total and unbound cortisol are normal in all these conditions. We conclude that unbound cortisol can be calculated in a simple and reliable way from total cortisol and CBG and permits a better evaluation of adrenal function, particularly in patients with altered CBG concentrations.

Effects of betamethasone on maternal plasma corticotropin releasing factor, ACTH and cortisol during pregnancy

Corticotropin releasing factor immunoactivity (CRFi) has been identified in the plasma of women in the second half of gestation. There are several lines of evidence supporting a placental source for this hormone. Regulation of placental CRFi is poorly understood. In this study, the effect of a long-acting glucorticoid on the release of placental CRFi was investigated. Eleven women in the third trimester of pregnancy had plasma samples measured for CRFi, ACTH and cortisol before and after receiving 12 mg betamethasone. There was a significant decrease in ACTH (p less than 0.05) and cortisol levels (p less than 0.01) but no change in CRFi. It is concluded that the secretion of CRFi by the placenta is not inhibited by the administration of betamethasone while maternal levels of cortisol and ACTH are lowered. These results suggest that the acute regulation of placental CRFi is distinct from the regulation of hypothalamic CRF.

Acute dopaminergic blockade by sulpiride stimulates beta-endorphin secretion in pregnant women

The pars intermedia of the pituitary gland is well developed in most animal species but rudimentary in adult human subjects. Unlike the anterior pituitary, the intermediate lobe metabolizes proopiomelanocorticotrophin (POMC) mainly to beta-endorphin and to alpha-melanotrophin (alpha-MSH). This activity of the pars intermedia is under an inhibitory dopaminergic control. Biochemical and immunohistochemical evidence suggests the hyperplasia of the intermediate lobe during human pregnancy. The present study demonstrates that an acute dopaminergic blockade by sulpiride dramatically increases plasma concentrations of beta-endorphin in pregnant women but not in non-pregnant women providing functional evidence for the intermediate lobe hypothesis.