Ovarian Progesterone Production Research Articles

FRI392 Functional Interrelationship Between Oxytocin And Bone Morphogenetic Proteins In Ovarian Steroidogenesis By Granulosa Cells

Abstract Disclosure: K. Yamamoto: None. Y. Nakano: None. N. Iwata: None. Y. Soejima: None. A. Suyama: None. T. Hasegawa: None. F. Otsuka: None. Oxytocin (OXT) is a neuropeptide that is produced in the hypothalamus and is secreted from the posterior pituitary. OXT has diverse physiological roles mediated by the OXT receptor (OXTR), including not only stimulation of uterine contractions during labor and peripheral functions of milk ejection during lactation but also functions in pair bonding, maternal nurturing, and social behavior related to the action of OXT on the brain. It has been shown that OXT and OXTR are expressed in ovarian granulosa cells (GCs) in several species including humans. Secretion of OXT by bovine GCs is reported to be increased after the preovulatory luteinizing hormone surge, which is coincident with an increase in progesterone secretion and a decrease in secretion of estradiol and androgen, suggesting a functional interrelationship between OXT and ovarian steroidogenesis. It has been demonstrated that application of OXT to cultures of GCs from preovulatory follicles in bovines, marmoset monkeys, and humans led to increases in progesterone production. However, the precise molecular mechanism by which OXT modulates ovarian steroidogenesis in GCs remains unknown. Bone morphogenetic proteins (BMPs), which belong to the transforming growth factor beta (TGF-β) superfamily, play important roles in steroidogenesis and cellular proliferation in ovarian follicles via autocrine/paracrine fashion. BMP ligands and receptors are expressed in a cell-dependent manner in the ovary and have a pivotal role in female fertility. Throughout folliculogenesis, BMPs commonly inhibit follicle-stimulating hormone (FSH)-induced progesterone production, and oocyte-derived factors BMP-6 and BMP-15 are known to act on GCs through BMP receptors and suppress FSH-induced progesterone synthesis. To clarify the reproductive role of OXT in ovarian steroidogenesis and its functional interaction with BMPs, the effects of OXT on ovarian steroidogenesis were investigated by using primary culture of rat GCs and human granulosa KGN cells. Here we found that the OXT receptor was expressed in both rat GCs and human KGN cells and that OXT treatment significantly increased FSH- and forskolin (FSK)-induced progesterone production, but not estradiol production, by rat GCs and KGN cells, respectively. In accordance with the effects of OXT on progesterone production, OXT enhanced mRNA levels of CYP11A1 and HSD3B2 induced by FSK in KGN cells. Of note, OXT enhanced the phosphorylation of SMAD1/5/9 and the mRNA level of ID1 induced by BMP-15, but not those induced by BMP-6, in KGN cells. It was also revealed that OXT application upregulated the expression of BMPR2, a crucial type-II receptor of BMP-15, and enhanced the BMP-15-induced expression of inhibitory SMAD6 by KGN cells. Taken together, it was shown that OXT enhances ovarian progesterone production with upregulation of BMP-15 activity, leading to a fine-tuning of ovarian steroidogenesis. Presentation: Friday, June 16, 2023

Activation of G protein-coupled estrogen receptor stimulates placental human chorionic gonadotropin expression through PKA-CREB signaling

The placenta-secreted human chorionic gonadotropin (hCG) is a hormone that plays a critical role in inducing ovarian progesterone production, which is required for maintaining normal pregnancy. The bioavailability of hCG depends on the expression of the beta-subunit of hCG (hCG-β) which is encoded by the chorionic gonadotropin beta (CGB) gene. G protein-coupled estrogen receptor (GPER) is a membrane estrogen receptor involved in non-genomic estrogen signaling. Estradiol (E2) has been shown to stimulate hCG production. However, the role of the GPER in regulating CGB expression remains unknown. In the present study, our results revealed that treatment with G1 upregulated CGB expression in two human choriocarcinoma cell lines, BeWo and JEG-3, and primary human cytotrophoblast cells. In addition, G1 treatment activated the cAMP-response element binding protein (CREB). Using a pharmacological inhibitor and siRNA-mediated knockdown approach, we showed that the stimulatory effect of G1 on CGB expression is mediated by the protein kinase A (PKA)-CREB signaling pathway. This study increases the understanding of the role of GPER in the human placenta. In addition, our results provide important insights into the molecular mechanisms that mediate hCG expression, which may lead to the development of alternative therapeutic approaches for treating placental diseases.

(101) Ovarian Hyperthecosis as a Cause of Hypersexualization in a Post-menopausal Female

Abstract Introduction Ovarian Hyperthecosis (OH) is a rare benign virilizing ovarian syndrome characterized by androgen overproduction due to stromal and thecal hyperplasia resulting in hirsutism and virilization(1). It is believed to be similar to polycystic ovarian syndrome (PCOS) however, presents with more robust androgen overproduction and an ovarian vein ratio of androstenedione/testosterone less than one, compared with values around 20 in pre-menopausal females and patients with PCOS(2). Specifically in post-menopausal women, the phenotypical presentation is due to unmasking of the increased thecal cell testosterone release which results from lack of granulosa cell mediated aromatization of testosterone to estradiol.(3) Some have described treatment of OH with medications that inhibit ovarian production of estrogen and progesterone especially in pre-menopausal women. However, results are mixed and oophrectomy seems to be the most effective treatment modality for OH(3). Objective Here we describe a case of OH resulting in elevated androgen levels and distressing hypersexualization in a post-menopausal female who was effectively treated with bilateral oophorectomy resulting in normalization of laboratory values and resolution of hypersexualization. Methods The patient is a 75-year-old female with past medical history significant for bipolar disorder, Sjogren’s syndrome and hypothyroidism who presented to the office for evaluation of recurrent vulvovaginitis and urinary tract infections related to vigorous and frequent sexual activity. She reported symptoms of hypersexuality developing a few years prior to presentation at which time she began engaging in sexual activity 2-3 times daily and masturbating with a variety of objects. She had also noted new heavy facial hair and scalp hair loss. There were no changes in her medical history at the time. She was bothered by the increased need for sexual stimulation and orgasm, prompting further evaluation and treatment. Her exam was notable for vulvar contact dermatitis, mild vulvovaginal atrophy, and no prolapse or urinary incontinence. Vaginal infection testing was negative. Results of an endocrine work up are summarized in Table 1. Abdominal imaging showed normal adrenal glands and ovaries. An MRI of the brain showed a normal pituitary gland. She had been started on Prozac by her psychiatrist, which reduced her libido but worsened her mania and therefore was discontinued. A diagnosis of OH was suspected and bilateral oophorectomy was planned. Results The patient underwent a laparoscopic bilateral salpingo-ophrectomy with surgical pathology confirming stromal hyperplasia and hyperthecosis. Post-operatively, her labs rapidly normalized. She noted normalization of her libido, significant improvement in vulvar contact dermatitis and increased scalp hair growth. Conclusions Bilateral oophorectomy in a post-menopausal woman with OH was an effective treatment to normalize androgen levels and restore normal libido resulting in resolution of vulvar contact dermatitis from excessive masturbation. Although an uncommon diagnosis, this disease is an important consideration in the workup of excess androgen production in post-menopausal women. Disclosure No

Localization of phosphatidylinositol 4-phosphate 5-kinase (PIP5K) α confined to the surface of lipid droplets and adjacent narrow cytoplasm in progesterone-producing cells of in situ ovaries of adult mice

Phosphatidylinositol(4,5)bisphosphate (PI(4,5)P2) produced by phosphatidylinositol phosphate 5 kinase (PIP5K) plays not only as a precursor of second messengers in the phosphoinositide signal transduction, but also multiple roles influencing a variety of cellular activities. From this viewpoint, the present study attempted to localize PIP5Kα in the ovaries in situ of adult mice. PIP5Kα-immunoreactivity was confined to the surfaces of lipid droplets (LDs) and their adjacent cytoplasm in progesterone-producing cells of the interstitial glands, corpora lutea and theca interna. The LDs often contained membranous tubules/lamellae along their surfaces and within their interior whose membranes were continuous with those delineating LDs composed of a monolayer of phospholipids and were partially PIP5Kα-immunoreactive. Although granulosa cells of healthy-looking follicles were immunonegative, as the atresia progressed, PIP5Kα-immunoreactivity first appeared in sparsely dispersed dot forms in mural cells of the follicular epithelia, and then were dominant in almost all mural cells that remained after desquamation of the antral cells. The present study provides evidence suggesting that PI(4,5)P2 locally synthesized by PIP5K in LDs is involved in the lipid transfer between lipid droplets (LDs) and the endoplasmic reticulum, which eventually regulates ovarian progesterone production through control of multiple dynamic activities of LDs. It is also suggested that PIP5Kα and PI(4,5)P2 are implicated in the modulation of programmed cell death and/or acquiring the ability of progesterone production in some follicular cells surviving atresia.

Activation of Ovarian Taste Receptors Inhibits Progesterone Production Potentially via NO/cGMP and Apoptotic Signaling.

Taste receptors are not only expressed in the taste buds, but also in other nongustatory tissues, including the reproductive system. Taste receptors can be activated by various tastants, thereby exerting relatively physiologic functions. The aim of this study was to investigate the effects and potential mechanisms underlying ovarian taste receptor activation on progesterone production using saccharin sodium as the receptor agonist in a pseudopregnant rat model. Taste 1 receptor member 2 (TAS1R2) and taste 2 receptor member 31 (TAS2R31) were demonstrated to be abundantly expressed in the corpora lutea of rats, and intraperitoneal injection of saccharin sodium can activate both of them and initiate their downstream signaling cascades. The activation of these ovarian taste receptors promoted nitric oxide (NO) production via endothelial nitric oxide synthase (eNOS). NO production then increased ovarian cyclic guanosine 3',5'-monophosphate (cGMP) levels, which, in turn, decreased ovarian cyclic adenosine 3',5'-monophosphate levels. In addition, the activation of ovarian taste receptors induced apoptosis, possibly through NO and mitogen-activated protein kinase signaling. As a result, the activation of ovarian taste receptors reduced the protein expression of steroidogenesis-related factors, causing the inhibition of ovarian progesterone production. In summary, our data suggest that the activation of ovarian taste receptors inhibits progesterone production in pseudopregnant rats, potentially via NO/cGMP and apoptotic signaling.

Characterization of gene expression in the hypothalamo-pituitary-gonadal axis during the preovulatory surge in the turkey hen

ABSTRACTA preovulatory surge (PS) of luteinizing hormone (LH) and progesterone triggers follicle ovulation, which is the first step of egg production and is orchestrated by the hypothalamo-pituitary-gonadal (HPG) axis. In the HPG axis, hypothalamic peptides, gonadotropin releasing hormone, and gonadotropin inhibitory hormone, control the production of follicle stimulating hormone and LH by the pituitary, which subsequently regulate ovarian production of estradiol and progesterone, respectively. The goal of this study was to characterize the HPG axis function of average egg producing hens by assessing plasma hormone profiles and hypothalamic, pituitary, and follicle gene expression outside and during the PS (n = 3 per group). Results were analyzed by a one-way ANOVA using the mixed models procedure of SAS. Plasma estradiol was not affected by the PS (P > 0.05), but plasma progesterone levels increased 8-fold during the PS when compared to basal progesterone levels (P < 0.05). HPG axis gene expression related to ovulation stimulation (e.g., GNRH, GNRHR, and LHB) was down-regulated during the PS; whereas gene expression related to follicle development (e.g., FSHB) was up-regulated during the PS. Additionally, in the hypothalamus and pituitary, estradiol receptor expression was up-regulated during the PS, whereas progesterone receptor expression was down-regulated during the PS. In the follicle cells, gene expression pertaining to progesterone (e.g., STAR), androgen (e.g., HSD17B1), and estradiol (e.g., CYP19A1) production was up-regulated during the PS. Prior to this study, the HPG axis had yet to be characterized during the PS in the turkey hen. This study showed that the PS significantly impacted gene expression in the hypothalamus, pituitary, and ovarian follicles. These results provide a foundation for further research into the regulation of ovulation and egg production in turkey hens.

The earliest stages of follicular development: Follicle formation and activation

The formation of primordial follicles to establish a reservoir of resting follicles and the gradual depletion of that reservoir to provide a succession of growing follicles are key to female fertility, but little is known about the regulation of these early stages of follicular development. This review summarizes the efforts of our laboratory to elucidate these critical processes in cattle. Primordial follicles first appear in fetal ovaries around the end of the first trimester of pregnancy (Day 90), during a decline in fetal ovarian production of estradiol and progesterone. In ovarian cortical pieces from 90 to 120-day-old fetuses, follicles form in vitro and estradiol or progesterone inhibits follicle formation, whereas the non-aromatizable androgen 5a-dihydrotestosterone (DHT) does not. Newly formed bovine follicles are not capable of activating within 2 days in vitro, but they can acquire the capacity to activate during a longer culture; estradiol and progesterone inhibit the acquisition of their capacity to activate. When primordial follicles first form in cattle, their oocytes are not yet in meiotic arrest and acquisition of competence to activate is correlated with their progression to meiotic arrest at the diplotene stage of first prophase. After they acquire the competence to activate, bovine primordial follicles can be stimulated to activate in vitro by insulin or kit ligand, whereas anti- Mullerian hormone (AMH) is inhibitory. Although few follicles progress to the secondary stage in vitro, addition of testosterone or vascular endothelial growth factor (VEGF) dramatically increased the incidence of that transition. Regulation of the earliest stages of follicular development is complex and far from understood; better understanding could lead to new interventions to enhance fertility.

Growth differentiation factor 9 promotes follicle-stimulating hormone-induced progesterone production in chicken follicular granulosa cells

The function of oocyte-derived growth differentiation factor 9 (GDF9) in ovarian follicles has thus far been poorly defined in avian species compared with the defined function in mammals. Our aim here is to investigate the effects of GDF9 on steroidogenesis and on chicken ovarian granulosa cell (GC) mitosis. Primary GCs from both prehierarchical (6–8 mm in diameter, phGCs) and preovulatory follicles (F1–F5, poGCs) were cultured in the presence or absence of the GDF9 protein. The progesterone (P4) levels in the culture medium were then measured by radioimmunoassay (RIA), and the expression levels of steroidogenesis genes were detected by quantitative PCR. We found that GDF9 alone showed no significant effect on the P4 levels by regulating the expression of steroidogenesis genes, such as STAR, CYP11A1 and HSD3B. Further experiments indicated that GDF9 promoted follicle-stimulating hormone (FSH)-induced P4 production and STAR expression. GDF9 also rescued the FSH-induced decrease of FSH receptor (FSHR) expression but had no effect on the forskolin-induced P4, STAR and forskolin-inhibited FSHR expression levels, suggesting that GDF9 might achieve its regulatory role of P4 by enhancing FSHR and STAR expression. In addition, GDF9 also promoted GC cell cycle progression, regulated the gene transcription of related genes, potentiated DNA replication and inhibited apoptosis. Interestingly, these effects differed between the phGCs and the poGCs. To our knowledge, this is the first report that illustrates the function of GDF9 on chicken GCs and the effects on ovarian steroidogenesis. Our findings highlight the regulation of central oocytes on the surrounding granulosa cells and emphasize the interaction between paracrine signals and endocrine hormones on ovarian progesterone production; these findings contribute to the understanding of the development of avian ovarian follicles.

Pregnancy stage determines the effect of chronic stress on ovarian progesterone synthesis.

Although stress-induced glucocorticoid release is thought to be a primary driver by which maternal stress negatively impacts pregnancy outcomes, the downstream neuroendocrine targets mediating these adverse outcomes are less well understood. We hypothesized that stress-induced glucocorticoid secretion inhibits pituitary hormone secretion, resulting in decreased ovarian progesterone synthesis. Using a chronic restraint model of stress in mice, we quantified steroid hormone production, pituitary hormones, and expression of ovarian genes that support progesterone production at both early ( day 5) and midpregnancy ( day 10). Females subjected to daily restraint had elevated baseline glucocorticoids during both early and midpregnancy; however, lower circulating progesterone was observed only during early pregnancy. Lower progesterone production was associated with lower expression of steroidogenic enzymes in the ovary of restrained females during early pregnancy. There were no stress-related changes to luteinizing hormone (LH) or prolactin (PRL). By midpregnancy, circulating LH decreased regardless of treatment, and this was associated with downregulation of ovarian steroidogenic gene expression. Our results are consistent with a role for LH in maintaining steroidogenic enzyme expression in the ovary, but neither circulating PRL nor LH were associated with the stress-induced inhibition of ovarian progesterone production during early pregnancy. We conclude that chronic stress impacts endocrine networks differently in pregnant and nonpregnant mammals. These findings underscore the need for further studies exploring dynamic changes in endocrine networks participating in pregnancy initiation and progression to elucidate the physiological mechanisms that connect stress exposure to adverse pregnancy outcomes.

Emmenagogue properties of Milicia excelsa (Welw.) C.C. Berg (Moraceae) based, at least in part, on its ability to correlate the activity of the hypothalamic-pituitary axis to that of the ovaries

Ethnopharmacological relevanceMilicia excelsa (Welw.) C.C. Berg (Moraceae) is a medicinal plant recommended over tropical Africa as a cure for several ailments including amenorrhea. This is the hallmark of an ovarian lesion or a dysfunction of the hypothalamic-pituitary-ovarian axis which may lead to infertility, osteoporosis or endometrial cancer. However, regardless these traditional claims, no scientific report dealing with emmenagogue properties has been reported yet. Aim of the studyTo bring scientific evidence to the curative action of the plant, we proposed evaluating the effects of a root aqueous extract of Milicia excelsa on female Wistar rat sexual maturation. Material and methodsThe study was performed in immature (45 days old) female Wistar rats orally treated with the root aqueous extract of Milicia excelsa at doses of 14, 77 and 140mg/kg BW/day for 7 and 15 consecutive days. Genistein (10mg/kg BW) served as the reference substance. Negative control animals, treated with the vehicle, were followed up for 7, 15, 30 and 45 days and rats were aged 52, 60, 75 and 90 days at these respective days. This allowed setting the nubile age of experimental animals and to determine the impact of treatments with genistein or the aqueous extract of Milicia excelsa on the age of rat sexual maturation. Since female rats do not have menstruation and that the normal menstrual cycle occurs because of changing levels of hormones made and secreted by the ovaries in response to hormonal signals from the pituitary gland, the effects of treatments were evaluated on the pituitary production of gonadotropins, the ovarian production of estradiol and progesterone, and uterine and vaginal growths. ResultsThe sexual maturation of untreated rats was set at 90 days old. This sexual maturation was indicated by the simultaneous elevation of gonadotropins (FSH and LH (p<0.01)) and ovarian hormones (estradiol (p<0.001) and progesterone (p<0.05)) in animals aged 90 days. Uterine and vaginal growths (p < 0.001) observed in these animals appear as the result of elevated level of estradiol. The root aqueous extract of Milicia excelsa displayed genistein-like effects and increased FSH and estradiol serum levels following both treatment periods (7 and 15 days). Estradiol serum concentration significantly increased following a 7-day treatment at the dose of 14mg/kg BW (p<0.001). This resulted in an increase in the uterine wet weight, uterine and vaginal epithelial heights (p<0.05). These results suggest that the root aqueous extract of Milicia excelsa reduced rats’ sexual maturation from 90 to 52 days. Moreover, animals’ body weight was not affected following treatment with Milicia excelsa. ConclusionThe root aqueous extract of Milicia excelsa may solve the problem of amenorrhea by synchronizing the activity of the hypothalamic-pituitary axis to the ovarian production of estradiol and progesterone. The unaltered body weight following treatments justifies at least in part, the traditional use of Milicia excelsa for primary and secondary amenorrhea.

Prolactin modulates luteal activity in the short-nosed fruit bat, Cynopterus sphinx during delayed embryonic development

The aim of this study was to evaluate the role of prolactin as a modulator of luteal steroidogenesis during the period of delayed embryonic development in Cynopterus sphinx. A marked decline in circulating prolactin levels was noted during the months of November through December coinciding with the period of decreased serum progesterone and delayed embryonic development. The seasonal changes in serum prolactin levels correlated positively with circulating progesterone (P) level, but inversely with circulating melatonin level during first pregnancy showing delayed development in Cynopterus sphinx. The results also showed decreased expression of prolactin receptor-short form (PRL-RS) both in the corpus luteum and in the utero-embryonic unit during the period of delayed embryonic development. Bats treated in vivo with prolactin during the period of delayed development showed significant increase in serum progesterone and estradiol levels together with significant increase in the expression of PRL-RS, luteinizing hormone receptor (LH-R), steroidogenic acute receptor protein (STAR) and 3β-hydroxysteroid dehydrogenase (3β-HSD) in the ovary. Prolactin stimulated ovarian angiogenesis (vascular endothelial growth factor) and cell survival (B-cell lymphoma 2) in vivo. Significant increases in ovarian progesterone production and the expression of prolactin-receptor, LH-R, STAR and 3β-HSD proteins were noted following the exposure of LH or prolactin in vitro during the delayed period. In conclusion, short-day associated increased melatonin level may be responsible for decreased prolactin release during November–December. The decline in prolactin level might play a role in suppressing P and estradiol-17β (E2) estradiol levels thereby causing delayed embryonic development in C. sphinx.

Metabolic endotoxaemia – a potential novel link between ovarian inflammation and impaired progesterone production

Introduction: Medical conditions such as obesity and inflammatory bowel disease are associated with impaired luteal function, menstrual disturbance and infertility. It is proposed that the disturbance in gut wall integrity (“leaky gut”) seen in these conditions may result in the passage of bacterial endotoxin (LPS) from the colonic lumen into the circulation that may initiate inflammation in the ovary and subsequently impair hormone production.Methods: Quantify the association between systemic levels of LBP, a marker of endotoxin exposure, and levels of inflammation in the ovary (follicular fluid IL-6), plus steroid hormone production in 45 women undergoing IVF treatment.Results: Endotoxaemia (LBP) were positively correlated with plasma CRP and inflammation within the ovary (follicular fluid IL-6). Furthermore, endotoxaemia was negatively correlated with progesterone production.Conclusion: The observed correlations, together with previously published animal studies linking endotoxin exposure to impaired luteal function, suggest that the translocation of bacterial endotoxin from the gut lumen into the circulation has the potential to interfere with progesterone production and result in luteal deficiency.

Enhanced LH action in transgenic female mice expressing hCGβ-subunit induces pituitary prolactinomas; the role of high progesterone levels

The etiology of pituitary adenomas remains largely unknown, with the exception of involvement of estrogens in the formation of prolactinomas. We have examined the molecular pathogenesis of prolactin-producing pituitary adenomas in transgenic female mice expressing the human choriongonadotropin (hCG) β-subunit. The LH/CG bioactivity is elevated in the mice, with consequent highly stimulated ovarian progesterone (P4) production, in the face of normal estrogen secretion. Curiously, despite normal estrogen levels, large prolactinomas developed in these mice, and we provide here several lines of evidence that the elevated P4 levels are involved in the growth of these estrogen-dependent tumors. The antiprogestin mifepristone inhibited tumor growth, and combined postgonadectomy estradiol/P4 treatment was more effective than estrogen alone in inducing tumor growth. Evidence for direct growth-promoting effect of P4 was obtained from cultures of primary mouse pituitary cells and rat somatomammotroph GH3 cells. The mouse tumors and cultured cells revealed stimulation of the cyclin D1/cyclin-dependent kinase 4/retinoblastoma protein/transcription factor E2F1 pathway in the growth response to P4. If extrapolated to humans, and given the importance of endogenous P4 and synthetic progestins in female reproductive functions and their pharmacotherapy, it is relevant to revisit the potential role of these hormones in the origin and growth of prolactinomas.

Insulin-Like Growth Factor Binding Protein-1 in the Ruminant Uterus: Potential Endometrial Marker and Regulator of Conceptus Elongation

Establishment of pregnancy in ruminants requires conceptus elongation and production of interferon-tau (IFNT), the pregnancy recognition signal that maintains ovarian progesterone (P4) production. These studies determined temporal and spatial alterations in IGF binding protein (IGFBP)-1 and IGFBP3 in the ovine and bovine uterus; effects of P4 and IFNT on their expression in the ovine uterus; and effects of IGFBP1 on ovine trophectoderm cell proliferation, migration, and attachment. IGFBP1 and IGFBP3 were studied because they are the only IGFBPs specifically expressed by the endometrial luminal epithelia in sheep. In sheep, IGFBP1 and IGFBP3 expression was coordinate with the period of conceptus elongation, whereas only IGFBP1 expression was coordinate with conceptus elongation in cattle. IGFBP1 mRNA in the ovine endometria was between 5- and 29-fold more abundant between d 12 and 16 of pregnancy compared with the estrous cycle and greater on d 16 of pregnancy than nonpregnancy in the bovine uterus. In sheep, P4 induced and IFNT stimulated expression of IGFBP1 but not IGFBP3; however, the effect of IFNT did not mimic the abundant increase observed in pregnant ewes. Therefore, IGFBP1 expression in the endometrium is regulated by another factor from the conceptus. IGFBP1 did not affect the proliferation of ovine trophectoderm cells in vitro but did stimulate their migration and mediate their attachment. These studies reveal that IGFBP1 is a common endometrial marker of conceptus elongation in sheep and cattle and most likely regulates conceptus elongation by stimulating migration and attachment of the trophectoderm.

Ovarian Steroidogenic Responsiveness to Exogenous Gonadotropin Stimulation in Young and Middle-Aged Female Rats

Reproductive aging in the female rat is associated with gradual declines in LH secretion and ovarian progesterone (P) production. This study examined whether the influences of aging on P levels reflect decreased ovarian responsiveness to gonadotropin stimulation, as opposed to changes in gonadotropin release. Young and middle-aged regularly cyclic female rats received sodium pentobarbital to block endogenous proestrous luteinizing hormone (LH) surges, followed by administration of various doses of human chorionic gonadotropin (hCG). Similar treatments were performed in middle-aged acyclic persistent-estrous (PE) females. Injection of hCG resulted in equivalent plasma hCG levels in each treatment group. At the lowest hCG dose tested, a significant rise in plasma P levels was observed in middle-aged cyclic rats, but not in young cyclic or middle-aged PE females. This unexpected finding may reflect accelerated follicular development in middle-aged cyclic females, as suggested by a previous study. At the inte...

Prolactin Regulation of Mammary Gland Development

Mammary morphogenesis is orchestrated with other reproductive events by pituitary-driven changes to the systemic hormone environment, initiating the formation of a mammary ductal network during puberty and the addition of secretory alveoli during pregnancy. Prolactin is the major driver of development during pregnancy via regulation of ovarian progesterone production (in many species) and direct effects on mammary epithelial cells (in all species). Together these hormones regulate two aspects of development that are the subject of intense interest: (1) a genomic regulatory network that integrates many additional spatial and temporal cues to control gene expression and (2), the activity of a stem and progenitor cell hierarchy. Amalgamation of these two aspects will increase our understanding of cell proliferation and differentiation within the mammary gland, with clear application to our attempts to control breast cancer. Here we focus on providing an over-view of prolactin action during development of the model murine mammary gland.

Impact of previous chemotherapy on ovarian production of estradiol, progesterone, and AMH: an in vitro controlled study

While numerous chemotherapy agents are known to cause ovarian follicle cell death, it is unknown whether chemotherapy has a detrimental effect on ovarian stromal cells. Our purpose was to assess the impact of chemotherapy on human ovarian stromal function by comparing in vitro estradiol (E2) and progesterone (P4) levels in ovarian cortical cultures from cancer patients who were and were not previously exposed to chemotherapy. To monitor follicle growth initiation in vitro, Anti-mullerian hormone (AMH) measurements were used.

Fibroblast Growth Factor-9, a Local Regulator of Ovarian Function

Fibroblast growth factor 9 (FGF9) is widely expressed in embryos and fetuses and has been shown to be involved in male sex determination, testicular cord formation, and Sertoli cell differentiation. Given its male gender bias, the ovary has not been reported to express FGF9, nor has a role in ovarian function been explored. We report here that FGF9 mRNA and protein are present in the rat ovary and provide evidence that supports a role for FGF9 in ovarian progesterone production. FGF9 mRNA levels as determined by real-time PCR were high in 4-d-old rat ovaries, thereafter declining and stabilizing at levels approximately 30% of d 4 levels at d 12-25. Levels of FGF9 mRNA in the ovary were significantly higher than that present in adult testis, at all ages studied. The FGF9 receptors FGFR2 and FGFR3 mRNAs were present in postnatal and immature rat ovary and appeared to be constitutively expressed. FGF9 protein was localized to theca, stromal cells, and corpora lutea and FGFR2 and FGFR3 proteins to granulosa cells, theca cells, oocytes, and corpora lutea, by immunohistochemistry. Follicular differentiation induced by gonadotropin treatment reduced the expression of FGF9 mRNA by immature rat ovaries, whereas the estrogen-stimulated development of large preantral follicles had no significant effect. In vitro, FGF9 stimulated progesterone production by granulosa cells beyond that elicited by a maximally stimulating dose of FSH. When the granulosa cells were pretreated with FSH to induce LH receptors, FGF9 was found not to be as potent as LH in stimulating progesterone production, nor did it enhance LH-stimulated production. The combined treatments of FSH/FGF9 and FSH/LH, however, were most effective at stimulating progesterone production by these differentiated granulosa cells. Analyses of steroidogenic regulatory proteins indicate that steroidogenic acute regulatory protein and P450 side chain cleavage mRNA levels were enhanced by FGF9, providing a mechanism of action for the increased progesterone synthesis. In summary, the data are consistent with a paracrine role for FGF9 in the ovary.

Seminal plasma regulates ovarian progesterone production, leukocyte recruitment and follicular cell responses in the pig

Seminal plasma (SP) acts to influence the uterine endometrium after mating, activating synthesis of embryotrophic cytokines and inflammatory changes that condition the tract for embryo implantation and establishing pregnancy. The objective of this study was to investigate in pigs whether the ovary might also be responsive to SP exposure. Prepubertal gilts were synchronised with exogenous gonadotrophins and received transcervical treatment with pooled boar SP or PBS; then the ovarian tissue was recovered at 34 h (preovulation) and on days 5 and 9 after treatment. The ovarian response was assessed by measuring ovulation rate, number and size of corpora lutea, ovarian leukocyte populations, progesterone production in vivo, as well as responses of retrieved granulosa cells cultured in vitro. In SP-treated gilts, leukocyte recruitment into the ovarian tissues was increased fourfold at 34 h, with macrophages comprising the most abundant cell lineage. There was no effect of SP on the number of oocytes ovulated; however, the weight of corpora lutea was increased in SP-treated gilts. SP also induced an increase in plasma progesterone content seen from day 5 to at least day 9 after treatment. In addition, granulosa cells and thecal tissue retrieved from preovulatory follicles of SP-treated gilts were more responsive in vitro to growth factor- and gonadotrophin-stimulated cell proliferation and progesterone synthesis. These results suggest that uterine exposure to SP influences immune cell trafficking in the ovary and enhances steroidogenesis in early pregnancy. The effects of SP on ovarian function potentially contribute to reproductive success in the pig.

Ovarian and placental production of progesterone and oestradiol during pregnancy in reindeer

Ovarian and placental production of progesterone and oestradiol during pregnancy in reindeer