Low-dose dexamethasone as a treatment for women with heavy menstrual bleeding: protocol for response-adaptive randomised placebo-controlled dose-finding parallel group trial (DexFEM)

INTRODUCTION

Heavy menstrual bleeding (HMB) diminishes individual quality-of-life and poses substantial societal burden. In HMB endometrium, inactivation of cortisol (by enzyme 11β hydroxysteroid dehydrogenase type 2 (11βHSD2)), may cause local endometrial glucocorticoid deficiency and hence increased angiogenesis and impaired vasoconstriction. We propose that 'rescue' of luteal phase endometrial glucocorticoid deficiency could reduce menstrual bleeding.

METHODS AND ANALYSIS

DexFEM is a double-blind response-adaptive parallel-group placebo-controlled trial in women with HMB (108 to be randomised), with active treatment the potent oral synthetic glucocorticoid dexamethasone, which is relatively resistant to 11βHSD2 inactivation. Participants will be aged over 18 years, with mean measured menstrual blood loss (MBL) for two screening cycles ≥50 mL. The primary outcome is reduction in MBL from screening. Secondary end points are questionnaire assessments of treatment effect and acceptability. Treatment will be for 5 days in the mid-luteal phases of three treatment menstrual cycles. Six doses of low-dose dexamethasone (ranging from 0.2 to 0.9 mg twice daily) will be compared with placebo, to ascertain optimal dose, and whether this has advantage over placebo. Statistical efficiency is maximised by allowing randomisation probabilities to 'adapt' at five points during enrolment phase, based on the response data available so far, to favour doses expected to provide greatest additional information on the dose-response. Bayesian Normal Dynamic Linear Modelling, with baseline MBL included as covariate, will determine optimal dose (re reduction in MBL). Secondary end points will be analysed using generalised dynamic linear models. For each dose for all end points, a 95% credible interval will be calculated for effect versus placebo.

ETHICS AND DISSEMINATION

Dexamethasone is widely used and hence well-characterised safety-wise. Ethical approval has been obtained from Scotland A Research Ethics Committee (12/SS/0147). Trial findings will be disseminated via open-access peer-reviewed publications, conferences, clinical networks, public lectures, and our websites.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov NCT01769820; EudractCT 2012-003405-98.

Anti-inflammatory steroid signalling in the human peritoneum

Peritoneal surface epithelial (PSE) cells participate in adhesion formation following inflammatory injury yet adjacent ovarian SE (OSE) cells regenerate without scarification after ovulation. OSE cells show inflammation-associated expression of 11beta hydroxysteroid dehydrogenase type 1 (11betaHSD1) enzyme, enabling intracrine generation of anti-inflammatory cortisol to minimise tissue damage. We asked if human PSE cells show an 11betaHSD1 response to pro-/anti-inflammatory stimulation and if so, how the 11-oxoreductase activity generated compares with OSE. PSE collected from premenopausal women undergoing surgery for benign gynaecological conditions were used to establish primary PSE cell cultures that were treated for 48 h with interleukin-1alpha (IL-1alpha) with/without anti-inflammatory steroid (cortisol or progesterone). mRNA levels corresponding to the genes of interest (11betaHSD1, 11betaHSD2, cyclooxygenase-2, COX-2) were measured by quantitative RT-PCR. IL-1alpha (0.5 ng/ml) stimulated 11betaHSD1 and COX-2 mRNA levels in PSE cells but 11betaHSD2 was unaffected. Cortisol (1 microM), not progesterone (1 microM), increased 11betaHSD1 mRNA and synergistically enhanced IL-1alpha action. Cortisol suppressed IL-1alpha-stimulated COX-2 more effectively than progesterone. PSE cells had a significantly lower basal 11-oxoreductase enzyme activity than OSE cells; IL-1alpha did not significantly increase the 11-oxoreductase activity in PSE cells but did so in OSE cells. We conclude that PSE cells respond to IL-1alpha and anti-inflammatory steroids in qualitatively similar ways as OSE. However, the enzymatic activity of 11betaHSD1 is lower in PSE and less responsive to IL-1alpha. This could help explain why peritoneal healing often leads to adhesion formation, whereas postovulatory ovarian healing is scar-free.

Effects of recombinant LH treatment on folliculogenesis and responsiveness to FSH stimulation

BACKGROUND

The role of LH in sensitizing antral follicles to FSH is unclear. LH is required for normal hormone production and normal oocyte and embryo development, but follicular responses to LH may depend upon the stage of development. Potential roles at the early follicular phase were explored in a clinical setting by employing a sequential approach to stimulation by recombinant human (r-h) LH followed by r-hFSH in women who were profoundly down-regulated by depo GnRH agonist.

METHODS

We employed a multi-centre, prospective, randomized approach. Women (n = 146) were treated in a long course high-dose GnRH agonist (Decapeptyl, 4.2 mg s.c.) protocol and were randomized to receive r-hLH (Luveris, 300 IU/day) for a fixed 7 days, or no r-hLH treatment. This was followed by a standard r-hFSH stimulation regime (Gonal-F, 150 IU/day). Ultrasound and hormone assessments of responses were measured at the start of r-hLH treatment, on FSH stimulation Days 0 and 8 and at the time of HCG administration.

RESULTS

The LH treatment was associated with increased small antral follicles prior to FSH stimulation (P = 0.007), and an increased yield of normally fertilized (2 PN) embryos (P = 0.03). There was no influence of the r-hLH pretreatment upon hormone profiles or ultrasound assessments during the FSH phase. Anti-mullerian hormone increased in both groups during the week prior to FSH stimulation (P = 0.002).

CONCLUSIONS

This sequential approach to the use of r-hLH in standard IVF showed a possible modest clinical benefit. The results support other recent work exploring up-regulated androgen drive upon follicular metabolism indicating that clinical benefit may be obtainable after further practical explorations of the concept.

Effects of inhibition of vascular endothelial growth factor at time of selection on follicular angiogenesis, expansion, development and atresia in the marmoset

This study determined the effects of inhibiting vascular endothelial growth factor (VEGF) at follicle selection. Marmosets were given an injection of VEGF antagonist, the VEGF Trap on Day 5 of the follicular phase and ovaries were evaluated on Day 10 or 15. Ovaries from controls were assessed on Day 5 (time of selection), Day 10 (peri-ovulatory) and Day 15 (luteal phase). At Day 10, ovaries of four of the five controls contained dominant follicles, while one had ovulated. VEGF Trap-treated ovaries also contained large follicles on Day 10, but VEGF inhibition had suppressed endothelial cell proliferation, leading to reductions in the thecal vascularization and plasma estradiol relative to controls. By Day 15, ovaries of controls contained active corpora lutea whereas ovaries of four of the five treated animals still contained large antral follicles similar in size to pre-ovulatory follicles, and one had small, avascular corpora lutea. However, these follicles had a restricted vasculature, increased incidence of activated caspase-3 staining and morphological features indicating they would become degenerative non-functional cysts. These results show that after follicle selection, VEGF is essential for angiogenesis and the generation of healthy ovulatory follicles and corpora lutea, but fluid accumulation can still occur in selected follicles in the absence of VEGF.

Thyroid hormone signaling in human ovarian surface epithelial cells

CONTEXT

Ovarian surface epithelial (OSE) cells express multiple nuclear hormone receptor genes, including those encoding thyroid hormone and estrogen receptors (TR and ER, respectively). Ovarian cancer is hormone-dependent, and epidemiological evidence links hyperthyroidism, inflammation of the ovarian surface, and increased risk of ovarian cancer.

OBJECTIVE

The objective of this study was to assess T3 action on human OSE cells in vitro, asking 1) is there evidence for (pre)receptor control, 2) is T3 inflammatory, and 3) does T3 affect ER expression?

DESIGN

Immunohistochemical analysis of fixed human ovaries and in vitro analysis of human OSE primary cell cultures were performed.

PATIENTS

Twelve women aged 29-50 yr (median, 41 yr) undergoing elective gynecological surgery for nonmalignant conditions were studied.

RESULTS

Messenger RNA transcripts for TRalpha1, TRalpha2, TRbeta1, and T3 activating deiodinase 2 and inactivating deiodinase 3 were present in primary OSE cell cultures by RT-PCR. TRalpha and TRbeta proteins were also localized to intact OSE by immunohistochemistry. Treatment of OSE cell cultures for 24 h with T3 caused dose-dependent mRNA expression of inflammation-associated genes: cyclooxygenase-2, matrix metalloproteinase-9, and 11betahydroxysteroid dehydrogenase type 1, determined by quantitative RT-PCR. Finally, treatment with T3 dose dependently stimulated ERalpha mRNA expression without affecting ERbeta1 or ERbeta2.

CONCLUSION

The ovarian surface is a potential T3 target. T3 exerts direct inflammatory effects on OSE cell function in vitro. OSE cell responses to T3 include increased expression of ERalpha mRNA, which encodes the ER isoform most strongly associated with ovarian cancer. This could help explain suggested epidemiological links between hyperthyroidism and ovarian cancer.

cAMP response element-binding (CREB) signalling and ovarian surface epithelial cell survival

cAMP response-element binding (CREB) transcription factors transduce cell survival responses to peptide hormones and growth factors in normal tissues and mutant CREB proteins are implicated in tumorigenesis. Ovarian cancer most frequently arises from the ovarian surface epithelium (OSE), possibly due to repeat inflammation-associated injury-repair episodes that promote neoplasia. We asked if post-receptor signalling involving the CREB family of proteins plays a role in OSE cell survival. In an ovine ovulation model, abundant expression of phospho-CREB/activating transcription factor (ATF) protein was detected immunohistochemically, strongly localised to OSE cells in the proximity of pre-ovulatory follicles. Treatment of primary sheep OSE cell cultures with LH stimulated cAMP accumulation and reduced apoptosis (caspase 3/7 activity) in response to serum withdrawal. When OSE cells were infected with an adenovirus containing a CRE-luciferase construct, exposure to LH and FSH induced CRE-directed transcription. Finally, when a non-phosphorylatable mutant of CREB (Ad CREB(S133A)) was adenovirally expressed, apoptosis measured by activation of caspases was increased several fold relative to that caused by transfection with wild-type CREB (Ad CREB(WT)) or lacZ (Ad lacZ). To test the potential clinical relevance of these findings, we expressed mutant CREB protein in normal human OSE cells from four women and a series of cell lines derived from human ovarian cancers. Infection with Ad CREB(S133A) markedly increased apoptosis in normal human OSE but had no detectable effect on apoptosis in any of the cancer cell lines. We conclude that CREB/ATF signalling is important for the maintenance of OSE cell survival in vitro and is altered in human cell lines derived from ovarian cancers.

Facial appearance is a cue to oestrogen levels in women

Although many accounts of facial attractiveness propose that femininity in women's faces indicates high levels of oestrogen, there is little empirical evidence in support of this assumption. Here, we used assays for urinary metabolites of oestrogen (oestrone-3-glucuronide, E1G) and progesterone (pregnanediol-3-glucuronide, P3G) to investigate the relationship between circulating gonadal hormones and ratings of the femininity, attractiveness and apparent health of women's faces. Positive correlations were observed between late follicular oestrogen and ratings of femininity, attractiveness and health. Positive correlations of luteal progesterone and health and attractiveness ratings were marginally significant. Ratings of facial attributions did not relate to hormone levels for women wearing make-up when photographed. There was no effect of sex of rater on the relationships between oestrogen and ratings of facial appearance. These findings demonstrate that female facial appearance holds detectable cues to reproductive health that are considered attractive by other people.

Menstrual cycle, trait estrogen level, and masculinity preferences in the human voice

Men with low testosterone (feminine men) invest in relationships and offspring more than men with high testosterone (masculine men). Women's attraction to testosterone dependent traits (e.g. masculine face shape) is enhanced during the late-follicular, fertile phase of the menstrual cycle. Attractive, feminine women have stronger preferences for masculine men as possible long-term partners than less attractive, masculine women. We manipulated 2 testosterone related vocal traits (voice pitch and apparent vocal-tract length) in voices to test if women prefer masculinized men's voices to feminized men's voices; masculinity preferences are enhanced at the fertile (late-follicular) menstrual cycle phase; the amount that masculinity preferences shift cyclically relates to average estrone-3-glucuronide concentration (the primary urinary metabolite of estrone, E3G). We found women displayed general masculinity preferences for men's voices; masculinity preferences were greater in the fertile (late-follicular) phase of the cycle than the non-fertile (early-follicular and luteal) phase; and this effect was most pronounced for women with low average E3G concentration. As feminine women (i.e. those with high average E3G levels) are most able to obtain investment even from masculine men, these women may not need to change their mating preference or strategy during the menstrual cycle as much as masculine women.

Inflammation-associated gene expression is altered between normal human ovarian surface epithelial cells and cell lines derived from ovarian adenocarcinomas

Ovulation is believed to contribute to the development of ovarian cancers that derive from the ovarian surface epithelium (OSE). The process of ovulation is synonymous with inflammation and inflammatory cytokines such as interleukin-1α (IL-1α) have recently been shown to induce both inflammatory and anti-inflammatory responses in human OSE (HOSE) cells. In this study we directly compared levels of IL-1α-induced gene expression by analysing the levels of 11β-hydroxysteroid dehydrogenase (11βHSD) types 1 (11βHSD-1) and 2 (11βHSD-2), cyclooxygenase-2 (COX-2), IL-1 receptor (IL-1R) and glucocorticoid receptor α (GRα) mRNA between normal HOSE cells and cell lines derived from poorly differentiated (SKOV-3, BG-1, PEO-4) and well-differentiated (PEO-14) ovarian adenocarcinoma. In HOSE cell cultures, and to a lesser extent PEO-14 cells, the basal mRNA levels of COX-2 and 11βHSD-1 were relatively high and further shown to be induced in response to IL-1α (for HOSE cells; >20-fold, P<0.05 and PEO-14 cells; >3fold, P<0.05). However, whereas HOSE cells expressed a low level of 11βHSD-2 mRNA that was only mildly responsive to IL-1α (1.3-fold, P<0.001), all cell lines exhibited a higher basal level of 11βHSD-2 mRNA that was in some cases further stimulated in PEO-4 cells (five-fold; P<0.05) or suppressed in SKOV-3 cells (two-fold; P<0.01) in response to IL-1α. All cells tested expressed IL-1R and, with the exception of BG-1, GRα. These results indicate that cell lines derived from ovarian cancers have lost the ability to respond normally to inflammatory cytokines such as IL-1α. The finding that normal OSE cells, in contrast to cell lines derived from patients with ovarian adenocarcinoma, abundantly express 11βHSD-1 mRNA but are essentially devoid of 11βHSD-2 mRNA supports the concept that the pattern of 11βHSD isoform gene expression is a defining feature of neoplastic cellular transformation, which might have particular relevance to the ovary.

Menstrual cycle, pregnancy and oral contraceptive use alter attraction to apparent health in faces

Previous studies demonstrating changes in women's face preferences have emphasized increased attraction to cues to possible indirect benefits (e.g. heritable immunity to infection) that coincides with periods of high fertility (e.g. the late follicular phase of the menstrual cycle). By contrast, here we show that when choosing between composite faces with raised or lowered apparent health, women's preferences for faces that are perceived as healthy are (i) stronger during the luteal phase of the menstrual cycle than during the late follicular, fertile phase, (ii) stronger in pregnant women than in non-pregnant women and (iii) stronger in women using oral contraceptives than in women with natural menstrual cycles. Change in preference for male faces was greater for short- than long-term relationships. These findings indicate raised progesterone level is associated with increased attraction to facial cues associated with possible direct benefits (e.g. low risk of infection) and suggest that women's face preferences are influenced by adaptations that compensate for weakened immune system responses during pregnancy and reduce the risk of infection disrupting foetal development.

Anti-inflammatory and proliferative responses in human and ovine ovarian surface epithelial cells

The majority of ovarian cancers (>90%) are believed to derive from the ovarian surface epithelium (OSE); a single layer covering the entire surface of the ovary. At ovulation, the OSE cell layer undergoes an inflammatory response, involving cell death and growth, in order to overcome ovarian surface rupture. Abnormalities during these processes are believed to contribute to the development of tumours. Using primary cultures of OSE cells, we have compared anti-inflammatory and proliferative responses directly between human and ovine OSE cells to further establish the use of ovine OSE cells as a suitable model system for the study of human OSE cells. In order to compare effects of inflammatory stimulation, expression and activity of 11βhydroxysteroid dehydrogenase (11βHSD) type 1 was measured in OSE cells in response to interleukin (IL)-1α. As previously identified in human OSE cells, treatment of ovine OSE cells with IL-1α stimulated a concomitant increase of 11βHSD type 1 mRNA (31-fold;P< 0.05) and oxoreductase activity, indicating an increased production of anti-inflammatory cortisol. To compare the growth of human and ovine OSE cells, OSE cell number was measured in response to treatment with gonadotropins or growth factors. In the presence of FSH, LH or human chorionic gonadotropin (hCG), ovine and human OSE cell growth was similarly stimulated >1.2-fold (P< 0.05). In the presence of connective tissue growth factor (CTGF) and more significantly insulin growth factor I (IGF-I), human and ovine OSE cell growth was also similarly stimulated >1.2-fold (P< 0.05) and >1.5-fold (P< 0.01), respectively. The induction of both human and ovine OSE cell growth by IGF-I or hCG was further shown to be dependent on activation of the MAP kinase/extracellular-signal-regulated kinase (ERK) pathway. Stimulation of ovine OSE cell growth by hepatocyte growth factor (HGF) was similarly shown to be ERK-dependent; however, for human OSE cells, HGF only mildly stimulated ERK phosphorylation and failed to stimulate OSE cell growth. The demonstration that human and ovine OSE cells share similarities at the level of cell signalling, gene expression and cellular growth supports the use of ovine OSE cells as a suitable model for the study of human OSE cells.

Steroid signalling in human ovarian surface epithelial cells: the response to interleukin-1alpha determined by microarray analysis

The human ovarian surface epithelium (HOSE) is a common site of gynaecological disease including endometriosis and ovarian cancer, probably due to serial injury-repair events associated with successive ovulations. To comprehend the importance of steroid signalling in the regulation of the HOSE, we used a custom microarray to catalogue the expression of over 250 genes involved in the synthesis and reception of steroid hormones, sterols and retinoids. The array included a subset of non-steroidogenic genes commonly involved in pro-/anti-inflammatory signalling. HOSE cells donated by five patients undergoing surgery for non-malignant gynaecological conditions were cultured for 48 h in the presence and absence of 500 pg/ml interleukin-1alpha (IL-1alpha). Total RNA was reverse-transcribed into biotin-labelled cDNA, which was hybridised to the array and visualised by gold-particle resonance light scattering and charge-coupled device (CCD) camera detection. Results for selected genes were verified by quantitative reverse-transcription PCR. In five out of five cases, untreated HOSE cells expressed genes encoding enzymes required for de novo biosynthesis of cholesterol from acetate and subsequent formation of C21-pregnane and C19-androstane steroids. Consistent with the inability of HOSE cells to synthesise glucocorticoids, oestrogens or 5alpha-reduced androgens de novo, CYP21, CYP19 and 5alpha-reductase were not detected. The only steroidogenic gene significantly up-regulated by IL-1alpha was 11beta-hydroxysteroid dehydrogenase type 1 (11betaHSD1). Other cytokine-induced genes were IL-6, IL-8, nuclear factor kappaB (NFkappaB) inhibitor alpha, metallothionein-IIA and lysyl oxidase: inflammation-associated genes that respond to glucocorticoids. The only steroidogenic gene significantly suppressed by IL-1alpha was 3betaHSD1. Other genes suppressed by IL-1alpha were aldehyde dehydrogenase (ALDH) 1, ALDH 10, gonadotrophin hormone-releasing hormone receptor, peroxisome proliferation-activated receptor-binding protein (PPAR-bp) and nuclear receptor subfamily 2 group F member 2. These results define a steroidogenic phenotype of cultured HOSE cells and provide a limited expression profile for genes with associated signalling functions. IL-1alpha co-ordinately induces 11betaHSD1 and a panel of glucocorticoid-regulated, inflammation-associated genes in HOSE cells, providing further evidence that cortisol generated by 11betaHSD1 could participate in the local resolution of inflammation associated with ovulation.

Effects of GnRH antagonist treatment on follicular development and angiogenesis in the primate ovary

Angiogenesis is required for normal follicular development but the role of gonadotrophins in the control of follicular angiogenesis remains to be elucidated. This study investigated the effects of treatment with GnRH antagonist in vivo on follicular development and angiogenesis in the marmoset. GnRH antagonist was administered on either follicular day 0 or day 5 of the 10-day follicular phase with ovaries collected on day 10. Ovaries from control marmosets were studied at day 5 (mid follicular phase) and day 10 (periovulatory period). Ovaries were fixed, serial sectioned and subjected to morphological analysis and immunocytochemistry to determine cell proliferation and follicular endothelial cell area and in situ hybridization to assess changes in expression of vascular endothelial growth factor (VEGF). Treatment with GnRH antagonist from day 0-10 resulted in an absence of dominant preovulatory follicles seen in controls. In the remaining tertiary follicles granulosa, theca and endothelial cell proliferation was reduced, resulting in a minor reduction in vascular density. However, VEGF mRNA expression was unaffected by treatment. Treatment from day 5-10 did not prevent development of ovulatory size follicles, but they were atretic and lacked VEGF mRNA. These results suggest that while VEGF expression in the preovulatory follicle is under gonadotrophic control it is not dependent on normal gonadotrophin secretion in tertiary follicles, indicating that there are other paracrine factors regulating VEGF expression in the developing ovarian follicle.

[Role of LH in folliculogenisis during the menstrual cycle]

LH participates, with FSH, in normal follicle growth. LH and the ovarian follicle LH and the egg Implication of LH in oocyte modification via paracrine mediation and via the action of somatic cells following stimulation of the receptors present on the granulosa cells. LH and ovulation Control of ovulation by the LH peak inducing, about 36 hours later, rupture of the follicle, secretion of progesterone, and formation of the corpus luteum. Activation of LH by a pro-inflammatory cascade during follicle rupture and, in response, an anti-inflammatory cascade leading to repair of the ovary surface.

WWOX: a candidate tumor suppressor gene involved in multiple tumor types

We previously reported the construction of a P1-derived artificial chromosome (PAC) contig encompassing a set of homozygous deletions of chromosome 16q23-24.1 found in primary ovarian tumor material and several tumor cell lines. Using these PAC clones in a cDNA selection experiment, we have isolated a Sau3A fragment homologous to the WWOX transcript (GenBank accession no. ) from normal human ovarian surface epithelial (HOSE) cells. We demonstrate the homozygous deletion of WWOX exons from ovarian cancer cells and three different tumor cell lines. We also identify an internally deleted WWOX transcript from a further primary ovarian tumor. In three of these samples the deletions result in frameshifts, and in each case the resulting WWOX transcripts lack part, or all, of the short chain dehydrogenase domain and the putative mitochondrial localization signal. Sequencing revealed several missense polymorphisms in tumor cell lines and identified a high level of single nucleotide polymorphism (SNP) within the WWOX gene. This evidence strengthens the case for WWOX as a tumor suppressor gene in ovarian cancer and other tumor types.

Gonadotropic control of ovarian follicular growth and development

Development-related paracrine cues that sensitize follicles to follicle stimulating hormone (FSH) and luteinizing hormone (LH) are crucial to the emergence of a single dominant follicle in each ovulatory menstrual cycle. Sex steroids, insulin-like growth factors and members of the transforming growth factor-beta superfamily are key players in the follicular paracrine system. FSH acts through membrane-associated granulosa cell receptors (FSHR) to stimulate granulosa cell proliferation and differentiation. The most responsive follicle at the beginning of the cycle is the first to produce estrogen and express granulosa cell LHR. Paracrine signalling activated by FSH and LH sustains growth and oestrogen secretion until an ovulation-inducing LH surge is discharged by the pituitary gland. LH then reprograms granulosa cell function, leading to terminal differentiation (luteinization) rupture of the follicle wall, and release of the fertilizable egg. The genes regulated by the LH surge orchestrate profound changes in sex steroid production, metabolism and action which are necessary for ovulation. Preovulatory granulosa cells also increase their ability to metabolise cortisone to cortisol, which may be part of a local anti-inflammatory mechanism to promote rapid healing of the ruptured ovarian surface.

Differentiation-dependent expression of connective tissue growth factor and lysyl oxidase messenger ribonucleic acids in rat granulosa cells

Searching for novel genes involved in tissue remodeling during ovarian folliculogenesis, we carried out differential display RT-PCR (DDRT-PCR) on RNA from gonadotropin-stimulated rat granulosa cells (GC). GC from preantral and early antral follicles in immature rat ovaries were cultured in serum-free medium containing no hormone (control), recombinant human FSH (10 ng/ml), 5alpha-dihydrotestosterone (DHT; 10(-6) M), or FSH plus DHT. Total cellular RNA was extracted from cells at 6, 12, 24, and 48 h of treatment for DDRT-PCR analysis, corresponding to an estimated 60% saturation of the messenger RNA (mRNA) population. Six distinct complementary DNA clones were obtained that reproduced the DDRT-PCR profile on a Northern blot of the corresponding RNA samples. Two of these clones detected transcripts that were strongly down-regulated by FSH. One corresponded to connective tissue growth factor (CTGF), a cysteine-rich secreted protein related to platelet-derived growth factor that is implicated in mitogenesis and angiogenesis, and a second was identical to lysyl oxidase (LO), a key participant in extracellular matrix deposition. In detailed expression studies, Northern analysis revealed a single, approximately 2.5-kb CTGF transcript maximally suppressed within 3 h of exposure to FSH with or without DHT and two LO transcripts ( approximately 3.8 and approximately 5.2 kb) maximally suppressed at 6 h. DHT alone did not affect CTGF mRNA, but strongly enhanced LO mRNA relative to the control value. In vivo, CTGF and LO transcripts were significantly suppressed in GC 48 h after equine CG injection (10 IU, ip) compared with untreated controls and were further reduced 12 h after administration of additional 10 IU hCG to induce luteinization. In situ hybridization confirmed GC in preantral/early antral follicles as principal sites of CTGF and LO mRNA expression. We conclude that expression of CTGF and LO mRNAs is inversely related to GC differentiation. The encoded proteins probably have roles in the regulation of tissue remodeling and extracellular matrix formation during early follicular development.

Role of ascorbic acid in promoting follicle integrity and survival in intact mouse ovarian follicles in vitro

Ascorbic acid has three known functions: it is necessary for collagen synthesis, promotes steroidogenesis and acts as an antioxidant. Within the ovary, most studies have concentrated on the role of ascorbic acid in luteal formation and regression and little is known about the function of this vitamin in follicular growth and development. Follicular growth and development were investigated in this study using an individual follicle culture system that allows the growth of follicles from the late preantral stage to Graafian morphology. Follicles were isolated from prepubertal mice and cultured for 6 days. Control media contained serum and human recombinant FSH. Further groups of follicles were cultured in the same media but with the addition of ascorbic acid at concentrations of either 28 or 280 micromol l(-1). Addition of ascorbic acid at the higher concentration significantly increased the percentage of follicles that maintained basement membrane integrity throughout culture (P < 0.001). Ascorbic acid had no effect on the growth of the follicles or on oestradiol production. Metalloproteinase 2 activity tended to increase at the higher concentration of ascorbic acid and there was a significant concomitant increase in the activity of tissue inhibitor of metalloproteinase 1 (P < 0.01). Follicles cultured without the addition of serum but with FSH and selenium in the culture media underwent apoptosis. Addition of ascorbic acid to follicles cultured under serum-free conditions significantly reduced apoptosis (P < 0.05). From these data it is concluded that ascorbic acid is necessary for remodelling the basement membrane during follicular growth and that the ability of follicles to uptake ascorbic acid confers an advantage in terms of granulosa cell survival.

Development-related increase in cortisol biosynthesis by human granulosa cells

Antiinflammatory mechanisms are important in ovulation and may be regulated by cortisol (F). We previously showed that after administration of human (h)CG for ovulation induction, luteinized granulosa cells (LGC) abundantly express 11beta-hydroxysteroid dehydrogenase type 1 (11betaHSD1) messenger RNA but not 11betaHSD type 2 (11betaHSD2) messenger RNA. 11ssHSD1 is responsible for the reversible formation of antiinflammatory F from its inactive precursor cortisone (E), whereas 11betaHSD2 unidirectionally converts F to E through 11-oxidation. This pattern of gene expression predicts that LGC from periovulatory follicles would show increased activation of E to F, compared with granulosa cells from immature follicles (IGC), and that follicular fluid concentrations of E and F would alter accordingly. To test this hypothesis, we isolated IGC, thecal cells (TC), and follicular fluid, from ovaries of cyclic women, removed during surgery for benign gynecological disease. LGC and follicular fluid were aspirated from periovulatory follicles, 35 h after hCG injection, in patients undergoing in vitro fertilization treatment. In an 11betaHSD assay based on interconversion of tritiated E and F by cell suspensions in vitro, IGC (% conversion, 0.6 +/- 0.4, mean +/- SEM) and collagenase-dispersed TC (0.2 +/- 0.1%) were unable to convert E to F, whereas LGC (36.3 +/- 3.7%) were highly efficient at this reaction. Immature granulosa cells, LGC, and (to a lesser extent) TC were all able to convert F to E. Correspondingly, follicular fluid concentrations of total F and F:E ratios were significantly higher in periovulatory follicles, compared with immature follicles. Culturing IGC for 48 h in the presence of hFSH resulted in increased 11betaHSD1 reductase activity, paralleling stimulation of estrogen (aromatase activity) and progesterone biosynthesis. Similar treatment with hLH did not influence 11betaHSD1 reductase activity, except in a patient with more mature IGC, which also showed a significant increase in E-to-F conversion, as well as progesterone synthesis in response to hLH. These data confirm that 11betaHSD activity in the human ovary is developmentally regulated and gonadotropin responsive, favoring metabolism of F to E in immature follicles and E to F in periovulatory follicles. Increased formation of F by LGC in periovulatory follicles is consistent with an antiinflammatory function for this glucocorticoid at ovulation.

The Parkes lecture: controlled ovarian stimulation in women

Recent advances in knowledge of the endocrine and paracrine mechanisms that regulate human ovarian folliculogenesis have been parallelled by the introduction into clinical practice of new drugs that can be used safely and effectively to stimulate ovarian function in infertile women. Most notably, recombinant DNA technology has been applied to the production of molecularly pure forms of the gonadotrophins, FSH and LH, opening the way to the development of improved strategies for manipulating the ovarian paracrine system. The clinical objectives of controlled ovarian stimulation fall into two categories, depending on patient needs: (1) induction of multiple follicles from which mature oocytes can be harvested for use in assisted reproduction protocols such as in vitro fertilization and embryo transfer; or (2) induction of spontaneous ovulation of a single mature follicle so that conception might occur in vivo. This review summarizes the physiological principles upon which the use of gonadotrophins for clinical purposes is based, highlighting new opportunities for improved treatment as a result of the availability of recombinant FSH and LH.

The Parkes lecture: controlled ovarian stimulation in women

Recent advances in knowledge of the endocrine and paracrine mechanisms that regulate human ovarian folliculogenesis have been parallelled by the introduction into clinical practice of new drugs that can be used safely and effectively to stimulate ovarian function in infertile women. Most notably, recombinant DNA technology has been applied to the production of molecularly pure forms of the gonadotrophins, FSH and LH, opening the way to the development of improved strategies for manipulating the ovarian paracrine system. The clinical objectives of controlled ovarian stimulation fall into two categories, depending on patient needs: (1) induction of multiple follicles from which mature oocytes can be harvested for use in assisted reproduction protocols such as in vitro fertilization and embryo transfer; or (2) induction of spontaneous ovulation of a single mature follicle so that conception might occur in vivo. This review summarizes the physiological principles upon which the use of gonadotrophins for clinical purposes is based, highlighting new opportunities for improved treatment as a result of the availability of recombinant FSH and LH.

Regulation of 11beta-hydroxysteroid dehydrogenase type 1 gene expression by LH and interleukin-1beta in cultured rat granulosa cells

Granulosa cells from preovulatory follicles show increased expression of 11beta-hydroxysteroid dehydrogenase type 1 (11betaHSD1) at the time of ovulation. As ovulation may be an inflammatory process, this may be a mechanism of local enhancement of the activity of anti-inflammatory glucocorticoids. In this study, we examined direct effects of LH, the proinflammatory cytokine, interleukin-1beta (IL-1beta), and pharmacological activators of protein kinase A (PKA) (forskolin and dibutyryl (db) cAMP) and PKC (LH-releasing hormone and phorbol 12-myristate 13-acetate (PMA)) signalling on the expression of 11betaHSD1 mRNA in vitro. Granulosa cells from immature female rat ovaries were cultured (pretreatment) in serum-free medium 199 containing recombinant human (rh) FSH (1 ng/ml) for 48 h to induce responsiveness to LH. Cell monolayers were then washed and cultured (test treatment) for a further 12 h in the presence of rhLH (0-100 ng/ml), IL-1beta (0-50 ng/ml), or both. Total RNA was extracted from granulosa cell monolayers and taken for quantitative ribonuclease protection analysis of 11betaHSD1 mRNA. The low level of 11betaHSD1 mRNA detectable in unstimulated (control) cultures was increased approximately twofold by the 48-h pretreatment with rhFSH. Subsequent exposure to rhLH (1-100 ng/ml) for a further 12 h dose-dependently increased 11betaHSD1 mRNA expression by an additional two- to threefold. Forskolin (10 microM), db-cAMP (2 mM), LH-releasing hormone (LHRH; 1 microM) and PMA (200 nM) were also stimulatory. IL-1beta (0.05-50 ng/ml) stimulated 11betaHSD1 mRNA expression in a dose-related manner, both in the absence and in the presence of rhLH (3 ng/ml). The interaction between IL-1beta (5 ng/ml) and rhLH (3 ng/ml) was additive. Co-treatment with a 50-fold excess of IL-1 receptor antagonist fully reversed the action of IL-1beta. We conclude that 11betaHSD1 mRNA expression in functionally mature granulosa cells is directly stimulated by gonadotrophins and IL-1beta in vitro, potentially involving post-receptor signalling via PKA- and PKC-mediated pathways. Thus both LH and IL-1beta may serve physiological roles in the upregulation of 11betaHSD1 gene expression by granulosa cells in ovulatory follicles.

Regulation of 11beta-hydroxysteroid dehydrogenase isoforms and glucocorticoid receptor gene expression in the rat uterus

Glucocorticoids are known to have diverse effects on the uterus, generally believed to be mediated by the glucocorticoid receptor (GR). To date, two isoforms of the enzyme 11beta-hydroxysteroid dehydrogenase (11betaHSD) have been identified, namely 11betaHSD1 and 11betaHSD2, which interconvert active and inactive glucocorticoids and regulate local levels of hormones available to the GR in target tissues. The aim of the present study was to examine the uterine expression of 11betaHSD and GR mRNA. The interplay of these parameters is probably an important factor in determining actions of glucocorticoids on the uterus. Using Northern analysis we investigated the uterine expression of 11betaHSD1, 11betaHSD2 and GR mRNA in relation to serum levels of sex steroid hormones and uterine progesterone receptor mRNA expression in an animal model. Immature female rats were treated with 10 IU pregnant mare serum gonadotrophin (PMSG) followed by 10 IU human chorionic gonadotrophin (hCG) 48 h afterwards, and then killed at 0, 3, 6, 9, 12 and 24 h and 5 days after the hCG injection. Expression of both 11betaHSD1 and 11betaHSD2 mRNA in total uterine RNA was found to be up-regulated by more than 50% at 48 h after PMSG injection when oestradiol levels were also high. Following hCG treatment the expression of 11betaHSD1 and 11betaHSD2 further increased to reach maximal levels at 24 and 12 h respectively. GR mRNA expression was down-regulated by more than 50% by PMSG but gradually recovered after hCG injection. The results show that mRNA expression of 11betaHSD1, 11betaHSD2 and GR in the uterus is developmentally regulated, suggesting that these key determinants of glucocorticoid action may play an important role in uterine function.

Intragonadal regulation of male and female reproduction

FSH and LH are vital endocrine regulators of gonadal growth and function. However, locally produced--paracrine--steroidal and nonsteroidal substances mediate and modulate gonadotrophin action on gonadal cells. The testis and ovary share obvious morphological and functional homologies. Optimal functioning of the spermatogenic (Sertoli cells) and follicular (granulosa cells) epithelia depends on both endocrine stimulation by FSH and paracrine stimulation by androgen. In each gland, inhibins and related factors produced by FSH-stimulated Sertoli (testis) cells or granulosa (ovary) cells reciprocally modulate LH-stimulated androgen synthesis in neighbouring Leydig (testis) or thecal (ovary) cells. Thus androgens and inhibins are "unisex" paracrine regulators that operate in similar ways in both ovary and testis.

Expression of 11beta-hydroxysteroid dehydrogenase, glucocorticoid receptor, and mineralocorticoid receptor genes in rat ovary

A new concept in reproductive endocrinology is that the status of the ovary as a glucocorticoid target organ alters with follicular development. Evidence for a physiological role of glucocorticoids in the regulation of ovarian folliculogenesis has been strengthened by the discovery that 11beta-hydroxysteroid dehydrogenase (11betaHSD) mRNA expression in human granulosa cells is developmentally regulated. In this study, we quantified the pattern of expression and investigated the cellular location of 11betaHSD type 1 (11betaHSD1), 11betaHSD type 2 (11betaHSD2), glucocorticoid receptor (GR), and mineralocorticoid receptor (MR) mRNAs during follicular maturation in rat ovary. Immature female rats received treatment with eCG to induce preovulatory follicular development or eCG followed by hCG to induce luteinization. 11betaHSD1, 11betaHSD2, GR, and MR mRNAs were all detectable by ribonuclease protection assay in ovarian total RNA. Treatment with eCG alone caused an approximately 8-fold increase in the ovarian level of 11betaHSD1 mRNA, which rose to approximately 30-fold after additional treatment with hCG. Equine CG alone did not measurably affect the ovarian 11betaHSD2 mRNA level, but additional treatment with hCG reduced it to 34% of the control level. Expression of GR mRNA was unchanged by any gonadotropin treatment, while MR mRNA was down-regulated. A similar pattern of 11betaHSD1, 11betaHSD2, GR, and MR mRNA expression was observed in isolated granulosa cells. These results provide direct experimental evidence that 11betaHSD genes are gonadotropically regulated in the rat ovary, including granulosa cells, and are consistent with a shift in glucocorticoid metabolism from inactivation (due to oxidation by 11betaHSD2) to activation (reduction by 11betaHSD1) during hCG-induced granulosa cell luteinization.

Expression of oestrogen receptor alpha and beta in cultured human ovarian surface epithelial cells

Ovarian surface epithelial (OSE) cells participate in the formation of the ovarian cortex and are potential targets of oestrogen action. Oestrogens typically act through nuclear oestrogen receptors (ER) of which there are two known subtypes: ERalpha and ERbeta. In view of the potential importance of oestrogen as a local regulator of OSE cell function, we screened for ERalpha and ERbeta mRNA in primary OSE cell cultures by reverse transcriptase-polymerase chain reaction (RT-PCR) analysis, and used freshly isolated granulosa cells (GC) and granulosa-lutein cells (GLC) as positive controls. OSE cells, scraped from the ovarian surface of women undergoing laparotomy for benign gynaecological conditions, were cultured for up to 21 days to obtain enough cells for mRNA extraction. GC were obtained from spontaneously cyclic women undergoing total hysterectomy; while GLC were obtained from follicular aspirates of gonadotrophin-stimulated in-vitro fertilization patients. Total RNA (1 microg) was reverse transcribed into single-stranded cDNA for PCR (30 cycles) using primers selected to give specific ERalpha and ERbeta products. The ERalpha and ERbeta PCR products, authenticated by cloning and sequencing, were both weakly detectable by Southern analysis in cultured OSE cells and readily detectable in GC and GLC. These results show that cultured human OSE express both ERalpha and ERbeta mRNA, consistent with a role for oestrogen in the regulation of OSE cell function in vivo.

An anti-inflammatory role for glucocorticoids in the ovaries?

Roles of glucocorticoids in the direct regulation of ovarian function are poorly understood. This opinion paper highlights: (1) the inflammatory nature of the ovulatory process; (2) the contributions of cytokines and prostaglandins (hence inflammation) to ovulation; (3) the development-related pattern of 11beta-hydroxysteroid (11beta HSD) isoform expression (hence glucocorticoid metabolism) that occurs in ovarian follicles; and (4) the attribution of general anti-inflammatory properties of glucocorticoids to their interference with prostaglandin synthesis. We interpret the evidence cited to hypothesise that corticosteroids serve an anti-inflammatory role during ovulation, thereby promoting rapid healing of the wound left by follicular rupture. Other possible levels of glucocorticoid action in the ovaries are also considered.

Expression of oestrogen receptor isoforms in relation to enzymes of oestrogen synthesis in rat ovary

Oestrogen acts as a local regulator of follicular development, mediated by specific nuclear oestrogen receptors (ER). The aim of this study was to examine the gene expression of two ER isoforms, ERalpha and beta, in relation to oestrogenic enzymes, P450aromatase (P450arom) and 17betaHSD type1 (17betaHSD1) during follicular maturation and luteinization. Ovaries were obtained from immature rats treated with PMSG (10 iu for 48 h) followed by hCG (10 iu). Expression of ERalpha and beta was down-regulated by the treatment with PMSG. Following the hCG injection, further down-regulation of both ERs occurred. Conversely, expression of P450arom and 17betaHSD1 was initially up-regulated by PMSG and then rapidly down-regulated following injection of hCG. In isolated granulosa cell, ERbeta was the predominant ER while ERalpha was mainly expressed in residual ovary and corpora lutea (CL). These results indicate that ERalpha and ERbeta mRNAs are expressed in different cell types and are both down-regulated during gonadotrophin stimulated follicular maturation and luteinization in the rat ovary. Down-regulation of ER is accompanied by down-regulation of oestrogenic enzymes during luteinization. Thus both oestrogen production and reception are shut down as ovulation approaches.

Corticosteroid metabolism in human granulosa-lutein cells

OBJECTIVE

The aims of this study were to determine the type and level of 11 beta-hydroxysteroid dehydrogenase (11 beta HSD) in human granulosa-leutein cells (GLE) shortly before ovulation and to correlate activity with the outcome of treatment in patients undergoing in vitro fertilization and embryo transfer (IVF/ET).

DESIGN

GLC from 32 patients undergoing IVF/ET were tested for type and level of 11 beta HSD activity in relation to treatment outcome.

PATIENTS

Periovulatory follicles were aspirated by ultrasound guided transvaginal puncture following a standard controlled ovarian stimulation protocol, approximately 36 h after administering an ovulation-inducing dose of human chorionic gonadotrophin (HCG). GLC were separated from follicular fluid by density-gradient centrifugation and taken for measurement of 11 beta HSD activity in vitro; oocytes were used for IVF/ET.

MEASUREMENTS

Interconversion of cortisol (F) and cortisone (E), and dexamethasone (D) and 11-dehydrodexamethasone (DHD) was measured in standardized assays comprising incubation of GLC with 3H-labelled substrate, with separation of substrate and product by thin-layer radiochromatography.

RESULTS

Conversion of F to E varied from 10.5 to 30.9% while that of E to F was between 2.4 and 44.6%. In the GLC of 25 patients in whom both activities were measured, dehydrogenase (F to E) activity predominated in 13 and reductase (E to F) in 12. By contrast, D (substrate for 11 beta HSD2 but not 11 beta HSD1) showed less than 1% metabolism in this system while DHD (substrate for 11 beta HSD1 and 11 beta HSD2) was converted significantly (65.6-90.5%) to D in the four patients tested. There was no significant difference in the interconversion of F and E between patients who became pregnant and those who did not.

CONCLUSIONS

The dehydrogenase and oxoreductase reactions catalysed by 11 beta HSD both occur in granulosa-lutein cells at the time of follicular rupture, probably due to 11 beta HSD1. A lack of measurable conversion of dexamethasone to 11-dehydrodexamethasone suggests that dehydrogenation due to 11 beta HSD2 is low or absent. Neither type nor level of 11 beta HSD activity measured under the present assay conditions correlates with IVF outcome.

Differential expression of messenger ribonucleic acids encoding 11beta-hydroxysteroid dehydrogenase types 1 and 2 in human granulosa cells

In glucocorticoid target organs 11beta-hydroxysteroid dehydrogenase (11betaHSD) regulates the levels of active glucocorticoids available to glucocorticoid receptors. To date two isoforms of 11betaHSD, NADP-dependent type 1 11betaHSD (11betaHSD1) with predominant reductase activity and NAD-dependent type 2 11betaHSD (11betaHSD2) with dehydrogenase activity have been identified. Human ovarian granulosa cells have been shown to possess both dehydrogenase and reductase 11betaHSD activities and express 11betaHSD1 mRNA. However, whether 11betaHSD2 mRNA is also present or if the expression of either mRNA is developmentally regulated in the human ovary is unknown. We therefore used northern analysis to examine 11betaHSD1 and 11betaHSD2 mRNA levels in non-luteinized and luteinizing granulosa cells, corpora lutea (CL) and ovarian stroma obtained from human ovaries. Here we show that non-luteinized granulosa cells express relatively high levels of 11betaHSD2 mRNA but not 11betaHSD1. Conversely, luteinizing granulosa cells abundantly express 11betaHSD1 mRNA but not 11betaHSD2. CL also expresses 11betaHSD2 to lesser extent. Neither 11betaHSD mRNA is detectable in ovarian stroma. These results indicate that mRNAs encoding both 1lbetaHSD isozymes are present in human granulosa cells and they are developmentally--but differentially--regulated during preovulatory follicular development. The existence of developmentally regulated 11betaHSD in human granulosa cells is important new evidence that glucocorticoids, acting directly on the ovary, serve physiologically significant roles in the regulation of folliculogenesis.

Role of androgens in follicle maturation and atresia

Androgens are products of progestogen metabolism, intermediates in oestrogen biosynthesis and local regulators of ovarian function. Current understanding of intraovarian androgen formation, metabolism and action is reviewed, highlighting the contribution of androgens to the paracrine regulation of follicular maturation and atresia. Any factor that alters intracellular cAMP levels is a potential modulator of granulosa cell differentiation, and hence follicular development. Androgen appears to modulate gonadotrophin action on granulosa cells through amplification of cAMP-mediated post-receptor signalling. Here it is argued that during intermediate stages of follicular development, locally produced androgen acts via granulosa cell androgen receptors (AR) to promote follicle-stimulating hormone (FSH)-induced granulosa cell differentiation through amplifying cAMP-mediated post-receptor signalling. During late pre-ovulatory follicular development, higher concentrations of cAMP caused by stimulation with luteinizing hormone (LH) suppress granulosa cell proliferation and down-regulate some of the genes induced by FSH at earlier stages of pre-ovulatory development, including aromatase activity. Other granulosa cell functions, including progesterone synthesis, are enhanced by the high concentrations of cAMP induced by LH. There is experimental evidence from studies of rat and non-human primate (common marmoset) ovaries that AR levels in granulosa cells decline during pre-ovulatory follicular maturation. Since androgens augment FSH-induced cAMP formation and action, loss of AR could be a means of avoiding inappropriately high cAMP levels and hence avoiding premature activation of 'high-tone' cAMP-response genes that lead to atresia. Negative regulation of the granulosa cell AR could be part of the intra-ovarian mechanism that determines which follicle(s) becomes dominant and secretes oestrogen in the normal menstrual cycle.

Differential regulation of aromatase and androgen receptor in granulosa cells

During follicular development, androgen acts in three distinct ways. During the early stage of follicular differentiation, androgen acts as an enhancer of FSH-stimulated follicular differentiation. As follicular differentiation progresses, this effect is decreased and androgen is mainly utilized as a substrate for estrogen synthesis under increasing stimulation of FSH and LH. These two events are mediated by androgen receptor (AR) and aromatase (P450arom), respectively. In the rat and marmoset monkey, AR and P450arom are predominantly expressed in granulosa cells, and both are developmentally regulated. The expression of AR is highest in preantral/early antral follicles and gradually decreases as follicles mature, whereas expression of P450arom is increased as follicular differentiation progresses. We propose that differential regulation of these two androgen-utilizing factors contributes to the smooth transition of developing follicles from the early stage of differentiation to the fully mature ovulatory status. A failure of this transition due to improper androgen stimulation might result in follicular atresia.

Location and developmental regulation of androgen receptor in primate ovary

Locally produced androgens act via granulosa cell androgen receptors to modulate follicular responsiveness to gonadotrophins and thereby contribute to the paracrine regulation of ovarian function. We used quantitative androgen receptor immunocytochemistry to assess androgen receptor distribution in relation to pre-ovulatory follicular development in the common marmoset (Callithrix jacchus), a New World primate that ovulates two to four follicles in each approximately 28 day ovarian cycle. Ovaries from four adult females in the late follicular phase and from four in the luteal phase were fixed in 4% paraformaldehyde and subjected to an immunocytochemical analysis using a polyclonal androgen receptor antibody with detection by a standard avidin-biotin-peroxidase technique for alkaline phosphatase. Specific androgen receptor immunostaining occurred mainly in granulosa cell nuclei, with little or no specific staining in theca, stroma or oocytes. Granulosa cell androgen receptor immunostaining was most abundant in healthy preantral/early antral follicles, being low or absent from pre-ovulatory follicles and corpora lutea. Differences in granulosa cell androgen receptor immunostaining between immature (0.1-1.0 mm diameter) and pre-ovulatory (> or = 2.0 mm diameter) follicles were quantified using a videodensitometric analysis of grey-scale values. Readings were taken from the granulosa cell layers of 53 immature follicles and 10 pre-ovulatory follicles in late follicular phase ovaries. The average androgen receptor level in granulosa cells of immature follicles proved to be 4.2-fold higher (P < 0.01) than that in granulosa cells of pre-ovulatory follicles. Because other evidence suggests that paracrine androgen action in granulosa cells converts from stimulation to inhibition as follicles mature, we speculate that a development-related reduction in androgen receptor numbers serves to "protect' granulosa cells against the inhibitory action of androgen, thereby promoting pre-ovulatory follicular dominance in primate ovarian cycles.

Androgen receptor gene expression in rat granulosa cells: the role of follicle-stimulating hormone and steroid hormones

In rat ovary, androgen receptor (AR) is predominantly expressed in granulosa cells and is developmentally regulated. However, the exact mechanism that is responsible for the regulation of AR in granulosa cells has not been elucidated. The aim of this study was to examine 1) the levels of AR messenger RNA (mRNA) expression in granulosa cells from follicles of different size and 2) the effects of FSH, 8-bromo-cAMP, androgen, and estrogen on AR mRNA levels in granulosa cells in vitro. The abundance of AR mRNA was examined by ribonuclease protection assay using 32P-labeled AR complementary RNA probe and related to that of P450aromatase (P450arom) mRNA, a well established maker of granulosa cell differentiation. In large follicles (> 400 microns in diameter), the abundance of AR mRNA was decreased to 51% of that in small follicles (< 200 microns; P < 0.01), whereas the abundance of P450arom mRNA increased to 277% (P < 0.01). In medium follicles (200-400 microns), the abundance of AR mRNA was maintained (101%), whereas the abundance of P450arom mRNA increased to 202% of that in small follicles (P < 0.05). Treatment with FSH (0-300 ng/ml) or 8-bromo-cAMP (0-4 mM) induced P450arom mRNA in the cultured granulosa cells in a dose-dependent manner; however, it did not affect the levels of AR mRNA expression. Treatment with 5 alpha-dihydrotestosterone (1 microM) resulted in a significant reduction in the abundance of AR mRNA to 67% of the control value (P < 0.05). This effect was reversed by the addition of FSH (100 ng/ml; P < 0.01). Treatment with diethylstilbestrol (1 microM), alone or in combination with FSH (100 ng/ml), did not have any significant effect, although these treatments tended to decrease the abundance of AR mRNA to 81% and 85%, respectively. Both 5 alpha-dihydrotestosterone and diethylstilbestrol dramatically enhanced the abundance of FSH-induced P450arom mRNA compared to the effect of FSH alone. These results indicate that 1) the down-regulation of AR mRNA expression takes place in granulosa cells of preovulatory follicles; 2) FSH is not directly responsible for this event; and 3) androgen down-regulates AR mRNA expression in immature granulosa cells, and this effect is reversed by FSH. We conclude that androgen and FSH jointly regulate AR mRNA expression in rat granulosa cells.

GnRH-induced calcium mobilisation and inositol phosphate production in immature and mature rat ovarian granulosa cells

In rat ovarian granulosa cells the effects of GnRH are determined by the state of granulosa cell development with mainly inhibitory actions in immature cells and stimulatory actions in differentiated mature cells. These developmentally related effects of GnRH may arise from changes in either one or more of the signal transduction pathways activated by GnRH. The present study therefore measured downstream signalling events associated with the activation of the phospholipase C (PLC) signal transduction pathway in both mature and immature rat ovarian granulosa cells. Results showed that GnRH produced similar total inositol phosphate and intracellular calcium ([Ca2+]i) responses in both immature and mature granulosa cells. In contrast to the biphasic GnRH-induced [Ca2+]i response in pituitary gonadotropes, stimulation of the endogenously expressed GnRH receptor in both immature and mature granulosa cells produced a prompt monophasic rise in [Ca2+]i. This calcium transient was abolished by pretreating either cell type with a potent GnRH receptor antagonist or the PLC inhibitor U73122, demonstrating a GnRH receptor-specific activation of PLC. Similarly, pretreatment of cells with the [Ca2+]i antagonists thapsigargin or cyclopiazonic acid abolished the GnRH-induced calcium transient, whereas EGTA and nifedipine, a voltage-operated calcium channel (VOCC) antagonist, had no effect. These results suggest that in either immature or mature granulosa cells GnRH mobilises calcium from thapsigargin/cyclopiazonic acid-sensitive [Ca2+]i stores but does not involve the influx of extracellular calcium through VOCCs. We conclude that GnRH-induced stimulation of the PLC signal transduction pathway is independent of the stage of granulosa cell maturity and that alternative mechanisms account for the opposite effects of GnRH on gonadotrophin-induced steroidogenesis in mature and immature rat granulosa cells in vitro.

Modulation of granulosa cell deoxyribonucleic acid synthesis and differentiation by activin

FSH stimulates follicular growth through inducing granulosa cell proliferation. Our working hypothesis is that mitogenesis is facilitated by a locally produced growth/differentiation factor(s) that modulates FSH action in developing granulosa cells. The present study was undertaken to examine the effect of the related gonadal peptides activin and inhibin on granulosa cell proliferation. Monolayer cultures of granulosa cells isolated from preantral/early antral follicles in immature rat ovaries were established by incubation overnight in serum-free medium 199. Treatment was initiated with serum-free medium containing recombinant human (rh) activin and/or rh-inhibin in the presence or absence of FSH. After incubation for 18 h, medium was collected for progesterone determination (as a marker of cell differentiation), and the cell monolayers were incubated for 2 h in the presence of [3H]thymidine to measure DNA synthesis. Activin dose dependently (1-100 ng/ml) stimulated DNA synthesis (minimal effective dose, 1 ng/ml), whereas inhibin or FSH alone was without effect. When activin (1 ng/ml), but not inhibin, was present with FSH, the gonadotropin caused dose-dependent increases in [3H]DNA synthesis over a wide range of FSH concentrations (1-100 ng/ml). This property of activin was unaltered by the additional presence of inhibin (1-100 ng/ml). To analyze the role of cAMP in mediating the mitogenic action of FSH in the presence of activin, experiments were repeated substituting a membrane-permeable cAMP agonist, 8-bromo-cAMP (8br-cAMP; 0.1-3 mM). Similar to FSH, 8br-cAMP had no effect on granulosa cell DNA synthesis in the absence of activin. However, in the presence of activin (1 ng/ml) 8br-cAMP was stimulatory. The dose response to 8br-cAMP revealed a biphasic effect on DNA synthesis and differentiation: DNA synthesis rose to a maximum in the presence of 0.5 mM 8br-cAMP and declined thereafter. Progesterone synthesis only started to increase in the presence of 0.1 mM 8br-cAMP, rising to a maximum at 3 mM 8br-cAMP, at which concentration DNA synthesis was fully suppressed. We conclude that activin induces DNA replication in rat granulosa cells. In the presence of activin, FSH and 8br-cAMP are mitogens. These actions of FSH and 8br-cAMP occur at doses too low to stimulate steroidogenesis, emphasizing the role of intracellular cAMP tone in granulosa cell proliferation and differentiation.

Effects of growth hormone releasing hormone on rat ovarian steroidogenesis

During the last decade, it has been shown that each part of the somatotrophic axis can influence granulosa cell function. Growth hormone releasing hormone (GHRH) may be effective through the release of hypophyseal growth hormone (GH) and the subsequent increase of insulin-like growth factors (IGF). There is also some evidence that GHRH could act directly on ovarian function. The aim of this study was to determine the mechanism through which GHRH affects granulosa cell steroidogenesis in the ovary. Granulosa cells were obtained from immature, oestrogen- treated rats supplemented with or without follicle stimulating hormone (FSH) in vivo and were cultured for 48 h to evaluate steroid production. GHRH was administered either in vivo at the same time as FSH, or in vitro in the presence or absence of testosterone and FSH. Our results show that co-treatment with GHRH and FSH in vivo induced significant increases in plasma IGF-I concentrations and steroid production by cultured granulosa cells. The addition of GHRH to culture medium did not significantly alter steroid production by either non-differentiated (no FSH in vivo) or differentiated (FSH in vivo granulosa cells. In contrast, treatment in vitro with IGF-I significantly increased steroidogenesis in both cases. Our results suggest that any physiologically significant effect of GHRH on ovarian function is probably to be exerted via activation of the somatotrophic axis and the subsequent amplification of ovarian FSH responsiveness by IGF-I.

Regulation of 3 beta-hydroxysteroid dehydrogenase delta 5/delta 4-isomerase and cholesterol side-chain cleavage cytochrome P450 by activin in rat granulosa cells

Activin is a dimeric protein implicated in the local control of follicular steroidogenesis. Using cultured rat granulosa cells, we previously showed that the effect of activin on FSH-induced progesterone synthesis changes with preovulatory follicular development, from positive regulation in nondifferentiated (immature) granulosa cells to negative regulation in preovulatory (mature) granulosa cells. The aim of the present study was to assess development-related effects of activin on the expression of enzymes crucial to progesterone synthesis: cholesterol side-chain cleavage cytochrome P450 (P450scc) and 3 beta-hydroxysteroid dehydrogenase/delta 5-4-isomerase (3 beta HSD). Nondifferentiated granulosa cells were isolated from the ovaries of estrogen-pretreated immature female rats that received no other treatment; differentiated granulosa cells were obtained from similar animals treated for 48 h with human FSH to induce preovulatory follicular development. Cells were cultured for 48 h in serum-free medium with and without human FSH and/or recombinant activin-A, and medium was collected for measurement of progestagens (progesterone, pregnenolone, and 20 alpha-dihydroprogesterone). In cultures of nondifferentiated granulosa cells, activin augmented the FSH-induced production of all three steroids. In differentiated granulosa cells, activin suppressed the FSH-stimulated production of progesterone and 20 alpha-dihydroprogesterone, but had no effect on pregnenolone. The presence of exogenous pregnenolone increased the overall production of progesterone, but did not alter qualitative steroidogenic responses to activin. To assess the interaction between FSH and activin on 3 beta HSD and P450scc messenger RNA (mRNA) expression, Northern blot analyses were performed on total RNA isolated from cultured granulosa cells. Treatment in vitro with FSH alone markedly enhanced the abundance of both the 3 beta HSD and P450scc mRNA transcripts in nondifferentiated and differentiated granulosa cells. FSH-stimulated expression of P450scc mRNA was further enhanced by cotreatment of nondifferentiated granulosa cells with activin. However, activin had no consistent effect on FSH-stimulated expression of 3 beta HSD mRNA in nondifferentiated cells. In differentiated granulosa cells, both mRNAs were suppressed more than 50% by the presence of activin. We conclude that the in vitro effects of activin on FSH-induced expression of 3 beta HSD and P450scc mRNAs in rat GC are similar: initially stimulatory (P450scc) or without effect (3 beta HSD), then becoming completely inhibitory. The mechanism of this development-dependent change in the granulosa cell response to activin remains to be elucidated.

Developmental regulation of androgen receptor in rat ovary

Androgen receptor (AR) distribution and developmental regulation in the rat ovary were examined by semiquantitative immunohistochemistry. Ovarian AR mRNA levels were also determined by Northern analysis of total RNA and compared with the levels of cytochrome P450aromatase (P450arom), an established marker of preovulatory follicular maturity. Hypophysectomized immature female rats were treated with recombinant human (rh)-FSH and/or rh-LH, or human menopausal gonadotrophin (HMG). AR was predominantly located in granulosa cells. There was no indication of specific AR immunoreactivity in thecal cells, but scattered stromal cells did stain positively. In control and LH-treated ovaries, only small preantral/early antral follicles were present. Granulosa cells in these follicles showed intense AR immunostaining. Treatment with FSH, FSH and LH or HMG stimulated varying degrees of preovulatory follicular development. In these follicles, the intensity of AR immunostaining progressively declined as follicular development progressed. In intact immature rats treated with FSH, the abundance of ovarian AR mRNA was significantly decreased to 35% of the control value while combined treatment of FSH and LH resulted in further down-regulation of AR mRNA expression to 17% of the control value. A decrease in the abundance of AR mRNA was accompanied by a simultaneous increase in the abundance of P450arom mRNA. Similar results were obtained in hypophysectomized immature rats treated with FSH and LH, suggesting an inverse relationship between AR mRNA expression and granulosa cell maturity. These results suggest that (1) the AR is most abundant in the granulosa cells of rat ovaries and (2) the expression of AR and its mRNA are developmentally regulated, being down-regulated during FSH-stimulated preovulatory follicular development.