Hypersecretion Of Luteinizing Hormone Research Articles

The Effect of Virgin Coconut Oil on TNFα and Cytochrome P450 Aromatase Levels in Obese Female White Rats (Rattus norvegicus) Induced with a High-Fat Diet

Background: The high level of various proinflammatory cytokines due to adipocyte hypertrophy such as TNFα in obesity increases cytochrome-P450-aromatase, further inducing increased estrogen production, hypersecretion of Luteinizing Hormone and decreased Follicle Stimulating Hormone, resulting in impaired folliculogenesis, and chronic anovulation. Virgin Coconut Oil is rich in Medium Chain Fatty Acid and phytochemicals as anti-inflammatory. Aim: The aim of this study was to determine the effect of VCO on reducing TNFα and cytochrome-P450-aromatase levels in obese female white rats. Methods: Post test only control group, 24 rats were divided into 3 groups, namely: negative control group (K-), positive control group (K+), and treatment group (P). The K+ and P groups were induced using a high-fat diet for 10 weeks, then the P group was given VCO in weeks 7-10. On the first day of week 11, blood was taken from the orbital vein of the eyes of all rats for TNFα levels. Both examinations used ELISA kits. Data analysis used Shapiro Wilks normality test. The value of p>0.05, followed by hypothesis testing using one-way annova and post hoc Bonferroni. Results: Mean TNFα in the K- group: 141.71±8.87, K+ group: 15.09±19.30, P group: 162,09±13,57. Mean cytochrome-P450-aromatase levels in the K- group: 9.00±0.77, K+ group: 12.22±1.69, P group: 10.58±0.97. The mean levels of one way ANOVA analysis showed that the administration of VCO can significantly reduce TNFα levels (p=0.001) and significantly reduce Cytochrome-P450-aromatase levels (p=0.001). Conclusion: VCO administration can reduce TNFα levels and cytochorme-P450-aromatase levels in obese female white rats. Keywords: TNFα, cytochrome-P450-aromatase, infertility, obesity

PSIV-17 Postnatal Obesity Amplifies Gnrh-Induced Lh Release in Prenatal Testosterone-Treated Female Sheep

Abstract Polycystic ovary syndrome (PCOS) is the most common hormonal disorder in females of reproductive age. Hypersecretion of luteinizing hormone (LH), partly due to increased pituitary sensitivity to gonadotrophin-releasing hormone (GnRH), is a significant cause of infertility in women with PCOS. Moreover, obesity amplifies the severity of reproductive dysfunction in PCOS. In sheep, testosterone (T) excess during gestational days (GD) 30 to 90 results in GnRH-mediated LH hypersecretion and recapitulates the PCOS phenotype. This study investigated 1) if mid-gestation (GD 60 to 90) is the susceptibility window for programming pituitary hypersensitivity to GnRH, and 2) the contribution of postnatal obesity in modulating LH responsiveness to GnRH. Suffolk ewes received T propionate (T; 100 mg i.m.) or corn oil (C; vehicle) twice weekly from GD 60 to 90 (term = 147 d). At 5 mo of age, T lambs were assigned randomly to either a maintenance (100% of NRC requirements) or overfed diet (130% of NRC requirements), and Control lambs were fed the maintenance diet. During the anestrous period (late summer), ewes (n = 8/group; ~17 mo of age) received a GnRH bolus injection (2 ng/kg) intravenously every 1.5 h and blood samples were collected at 15-min intervals for a 6-h period. Despite animals being in seasonal anestrous, few endogenous LH pulses were evident during the 6 h-sampling period. To avoid confounding, only clear responses to GnRH challenge that occurred within 15 to 45 min after each GnRH injection were considered for further analyses. Mean number of exogenous GnRH-induced LH responses that met these criteria did not differ between groups and averaged 1.81 ± 0.27 pulses/animal. The parameters of these GnRH-induced responses were analyzed as one-way ANOVA with Tukey’s HSD post-hoc analysis. Mean LH pulse peak was greater (P < 0.05) in T overfed ewes (4.59 ± 0.49 ng/mL) compared with T maintenance (2.19 ± 0.61 ng/mL) and Control ewes (2.58 ± 0.53 ng/mL). Additionally, amplitude of LH pulses was greater (P < 0.05) in T overfed ewes (2.66 ± 0.39 ng/mL) compared with T maintenance (1.03 ± 0.48 ng/mL) and tended (P = 0.089) to be greater in T overfed compared with Control ewes (1.41 ± 0.42 ng/mL). LH pulse peak and amplitude in T maintenance did not differ from Control ewes. In conclusion, failure of GD 60 to 90 T treatment to increase GnRH responsiveness as opposed to our earlier finding of increased responsiveness in GD 30 to 90 T-treaded sheep indicates that the susceptibility window for programming pituitary hypersensitivity to GnRH lies between GD 30 to 60. Postnatal obesity may act as an independent activational signal in amplifying the pituitary sensitivity to GnRH in female sheep. This premise is supported by observations that obesity exacerbates pituitary-mediated LH hypersecretion in women with PCOS. Research support: NIH-NICHD (R01HD099096).

PMON325 Rare Presentation of Precocious Puberty Secondary to LH-Secreting Adenoma

Abstract Background Normal male puberty begins after 9 years of age with a concurrent rise in luteinizing hormone (LH) and follicle-stimulating hormone (FSH). These play distinct roles, with LH acting on Leydig cells to stimulate testosterone and secondary sex characteristics, while FSH promotes testicular growth by stimulating the maturation of seminiferous tubules. Clinical Case An 8-year 9-month-old male TV presented with a 1.5 year history of facial hair and 9 months of phallic growth, body odor and acne. Physical exam revealed phallic enlargement, Tanner stage I pubic hair and firm, borderline pubertal testes (4 cc bilaterally). Bone age was 9 years at a chronological age of 8 years 6 months. Laboratory evaluation was inconsistent with typical puberty – LH (9 mIU/mL, RR 0.0-0.3 mIU/mL) and testosterone (519 ng/dL, RR 2-8 ng/dL) were elevated while FSH was pre-pubertal (<0.1 mIU/mL, RR 0.0-2.8 mIU/mL) and androgens were only mildly elevated (androstenedione 0.363 ng/mL, RR 0.03-0.3; 17-OHP 155 ng/dL, RR<63 ng/dL). Head MRI revealed an anterior pituitary adenoma measuring 8×12×10 mm. After failing to respond to leuprolide, TV was initiated on spironolactone and anastrozole to minimize pubertal progression prior to transsphenoidal adenomectomy. Surgical pathology was positive for steroidogenic factor 1 but negative for LH, FSH and thyroid-stimulating hormone immunoreactivity. However, he had post-operative reduction of LH (0.4 mIU/mL, RR 0.0-0.3 mIU/mL) and testosterone (16 ng/dL, RR 2-8 ng/dL). Conclusions Normal male puberty follows a predictable sequence, beginning with testicular enlargement followed by body odor, pubic hair growth, phallic enlargement, voice change, and increased growth velocity. In TV, hypersecretion of LH led to testosterone production, causing secondary sex characteristics. However, his pre-pubertal FSH did not stimulate the testicular growth that typically heralds the onset of puberty. Digression from typical pubertal sequence and isolated high LH raised concern for a pathologic cause. Central precocious puberty (CPP) is most often idiopathic in females, although more commonly associated with CNS lesions in males. Rarely, precocious puberty results from a functioning gonadotroph adenoma. Less than 1% of these are hormonally active. If active, these more often secrete FSH or co-secrete FSH and LH, and typically require surgical resection given limited success of medical therapies. This case illustrates the distinct roles of FSH and LH in pubertal development. Departures from the typical sequence of development should expand one's differential to include etiologies resulting in nonconcurrent secretion of gonadotropins. Presentation: Monday, June 13, 2022 12:30 p.m. - 2:30 p.m.

Hysteroscopic and morphological evaluation of endometrium in reproductive age women with comorbid polycystic ovarian syndrome and chronic endometritis in the protocols of in vitro fertilization

Summary. Today, infertility, which is associated with polycystic ovary syndrome, is a pressing problem in obstetrics, gynecology and reproductive medicine. Polycystic ovary syndrome (PCOS) is a common endocrine disease that affects about 6 to 20 % of women of childbearing potential. Its main signs are ovulatory and menstrual dysfunction (including anovulation), increased levels of gonadotropin-releasing hormone, hypersecretion of luteinizing hormone, hyperandrogenemia, metabolic disorders and morphological changes in the endometrium and ovaries. The aim of the study – to evaluate hysteroscopic and morphological changes in the endometrium of women with infertility against the background of PCOS and chronic endometritis and to analyze the effect of a modified treatment regimen in the protocols of in vitro fertilization on the manifestations of chronic endometritis. Materials and Methods. We examined 140 women with endocrine infertility against the background of PCOS and chronic endometritis, which were divided into 2 study groups, depending on the cause and treatment approach for infertility, as well as 35 women with male-caused infertility who comprised the control group. All examined patients underwent hysteroscopy, targeted biopsy and immunohistochemical study of the endometrium. Histological study of the endometrium was performed by staining the tissue with hematoxylin and eosin according to a standard protocol in order to understand the structural changes of the endometrium in women of the study groups. Immunohistochemical testing involved the detection of CD138 using standard Daco antibody kits (Denmark). Results. Patients with PCOS and chronic endometritis used standard anti-inflammatory treatment which followed our modified protocol. This resulted in significantly reduced manifestations of chronic endometritis. The modified protocol includes inositol and alpha-lipoic acid in pre-pregnancy preparation; PRP therapy of the uterine cavity; and lipofundin infusions on day 2–3 of the menstrual cycle and on the day of embryo transfer. Conclusions. Histological examination of the endometrium with manifestations of stromal-adenomatous polyps revealed reduced signs of cytogenic stroma proliferation, decreased perivascular edema and the number of erythrocyte diapedesis. The number of glandular elements and the size of the glands also decreased

Accelerated Episodic Luteinizing Hormone Release Accompanies Blunted Progesterone Regulation in PCOS-like Female Rhesus Monkeys (Macaca Mulatta) Exposed to Testosterone during Early-to-Mid Gestation

Background/Aims: Ovarian theca cell hyperandrogenism in women with polycystic ovary syndrome (PCOS) is compounded by androgen receptor-mediated impairment of estradiol and progesterone negative feedback regulation of episodic luteinizing hormone (LH) release. The resultant LH hypersecretion, likely the product of accelerated episodic release of gonadotropin-releasing hormone (GnRH) from the median eminence of the hypothalamus, hyperstimulates ovarian theca cell steroidogenesis, enabling testosterone (T) and androstenedione excess. Prenatally androgenized (PA) female monkeys exposed to fetal male levels of T during early-to-mid gestation, when adult, demonstrate PCOS-like traits, including high T and LH levels. This study tests the hypothesis that progesterone resistance-associated acceleration in episodic LH release contributes to PA monkey LH excess. Methods: A total of 4 PA and 3 regularly cycling, healthy control adult female rhesus monkeys of comparable age and body mass index underwent (1) a 10 h, frequent intravenous sampling assessment for LH episodic release, immediately followed by (2) IV infusion of exogenous GnRH to quantify continuing pituitary LH responsiveness, and subsequently (3) an SC injection of a progesterone receptor antagonist, mifepristone, to examine LH responses to blockade of progesterone-mediated action. Results: Compared to controls, the relatively hyperandrogenic PA females exhibited ~100% increase (p = 0.037) in LH pulse frequency, positive correlation of LH pulse amplitude (p = 0.017) with androstenedione, ~100% greater increase (p = 0.034) in acute (0–10 min) LH responses to exogenous GnRH, and an absence (p = 0.008) of modest LH elevation following acute progesterone receptor blockade suggestive of diminished progesterone negative feedback. Conclusion: Such dysregulation of LH release in PCOS-like monkeys implicates impaired feedback control of episodic release of hypothalamic GnRH reminiscent of PCOS neuroendocrinopathy.

Kisspeptin mRNA expression is increased in the posterior hypothalamus in the rat model of polycystic ovary syndrome.

Hypersecretion of luteinizing hormone (LH) is a common endocrinological finding of polycystic ovary syndrome (PCOS). This derangement might have a close relationship with hypothalamic kisspeptin expression that is thought to be a key regulator of gonadotropin-releasing hormone (GnRH). We evaluated the relationship between the hypothalamic-pituitary-gonadal axis (HPG axis) and kisspeptin using a rat model of PCOS induced by letrozole. Letrozole pellets (0.4 mg/day) and control pellets were placed subcutaneously onto the backs of 3-week-old female Wistar rats. Body weight, vaginal opening and vaginal smear were checked daily. Blood and tissues of ovary, uterus and brain were collected at 12-weeks of age. An hypothalamic block was cut into anterior and posterior blocks, which included the anteroventral periventricular nucleus (AVPV) and the arcuate nucleus (ARC), respectively, in order to estimate hypothalamic kisspeptin expression in each area. The letrozole group showed a similar phenotype to human PCOS such as heavier body weight, heavier ovary, persistent anovulatory state, multiple enlarged follicles with no corpus luteum and higher LH and testosterone (T) levels compared to the control group. Kisspeptin mRNA expression in the posterior hypothalamic block including ARC was higher in the letrozole group than in the control group although its expression in the anterior hypothalamic block was similar between groups. These results suggest that enhanced KNDy neuron activity in ARC contributes to hypersecretion of LH in PCOS and might be a therapeutic target to rescue ovulatory disorder of PCOS in the future.

Thecal cell sensitivity to luteinizing hormone and insulin in polycystic ovarian syndrome

This study examined whether a defect of steroid synthesis in ovarian theca cells may lead to the development of PCOS, through contributions to excess androgen secretion.Polycystic ovarian syndrome (PCOS) is one of the leading causes of infertility worldwide affecting around 1 in 10 of women of a reproductive age. One of the fundamental abnormalities in this syndrome is the presence of hormonal irregularities, including hyperandrogenemia, hyperinsulinemia and hypersecretion of luteinizing hormone (LH). Studies suggest that insulin treatment increases progesterone and androstenedione secretion in PCOS theca cells when compared to insulin treated normal theca cells. Furthermore the augmented effects of LH and insulin have been seen to increase ovarian androgen synthesis in non-PCOS theca cultures whilst also increasing the expression of steroidogenic enzymes specific to the PI3-K pathway.Our examination of primary thecal cultures showed an increase in both the expression of the steroidogenic enzyme CYP17 and androgen secretion in PCOS theca cells under basal conditions, when compared to non-PCOS cells. This was increased significantly under treatments of LH and insulin combined.Our results support the previous reported hypothesis that a dysfunction may exist within the PI3-K pathway. Specifically, that sensitivity exists to physiological symptoms including hyperinsulinemia and hyper secretion of LH found in PCOS through co-stimulation. The impact of these findings may allow the development of a therapeutic target in PCOS.

Developmental programming: Impact of prenatal exposure to bisphenol-A and methoxychlor on steroid feedbacks in sheep

Bisphenol-A (BPA), a polymer used in plastics manufacturing, and methoxychlor (MXC), a pesticide, are endocrine disrupting compounds with estrogenic and anti-androgenic properties. Prenatal BPA or MXC treatment induces reproductive defects in sheep with BPA causing prepubertal luteinizing hormone (LH) hypersecretion and dampening of periovulatory LH surges and MXC lengthening follicular phase and delaying the LH surge. In this study, we addressed the underlying neuroendocrine defects by testing the following hypotheses: 1) prenatal BPA, but not MXC reduces sensitivity to estradiol and progesterone negative feedback, 2) prenatal BPA, but not MXC increases pituitary responsiveness to gonadotropin releasing hormone (GnRH), and 3) prenatal BPA dampens LH surge response to estradiol positive feedback challenge while prenatal MXC delays the timing of the LH surge. Pregnant sheep were treated with either 1) 5mg/kg/day BPA (produces approximately twice the level found in human circulation, n=8), 2) 5mg/kg/day MXC (the lowest observed effect level stated in the EPA National Toxicology Program's Report; n=6), or 3) vehicle (cotton seed oil: C: n=6) from days 30 to 90 of gestation. Female offspring of these ewes were ovariectomized at 21months of age and tested for progesterone negative, estradiol negative, estradiol positive feedback sensitivities and pituitary responsiveness to GnRH. Results revealed that sensitivity to all 3 feedbacks as well as pituitary responsiveness to GnRH were not altered by either of the prenatal treatments. These findings suggest that the postpubertal reproductive defects seen in these animals may have stemmed from ovarian defects and the steroidal signals emanating from them.

Developmental Programming: Prenatal Androgen Exposure Alters the Gonadotroph Population of the Ovine Pituitary Gland

In utero exposure of the female foetus to androgens during development disrupts the reproductive axis and results in hypersecretion of luteinising hormone (LH) (but not follicle-stimulating hormone) in postnatal life. Abnormalities in the neural circuits controlling hypothalamic gonadotrophin-releasing hormone have been documented; however, androgens could also programme abnormalities in the pituitary gland. Ovine foetuses were exposed to either testosterone propionate or the non-aromatisable androgen dihydro-testosterone from days 30-90 of gestation (term 147 days) and the effects on the functional morphology of the pituitary were determined. Exogenous testosterone propionate exposure resulted in pituitary glands in adult male and female sheep that were 40% heavier than controls. Because this effect was not observed in the dihydro-testosterone-exposed animals, these actions are mediated via the oestrogen receptor (ER). No significant differences were apparent in 90- or 140-day foetuses. There was no difference between control and androgen-exposed animals in the density of LHβ or ERα immunoreactive cells in the pituitary although the density of follicle-stimulating hormone-β immunoreactive cells was lower in the testosterone-treated animals. The percentage of cells co-localising LHβ and ERα was lower in the testosterone-treated ewes and this may, in part, explain a reduced ability to respond to steroid feedback. Thus, enlargement of the pituitary gland, coupled with a reduced sensitivity to oestrogen negative-feedback, may contribute to the hyper-secretion of LH observed in animals that have been exposed to excess androgens during foetal life.

Developmental Programming: Gestational Testosterone Treatment Alters Fetal Ovarian Steroidogenic Gene Expression.

Gestational administration of testosterone increases ovarian androgen receptor protein expression in the fetus and culminates in hypersecretion of luteinizing hormone (LH), hyperestrogenism, persistent ovarian follicles, and oligo-/anovulation in adults. Since steroidogenic potential of the ovary gets established during fetal life, we hypothesized that maternal testosterone excess also alters steroidogenic enzyme expression within the fetal ovine ovary. Pregnant Suffolk ewes were treated with testosterone proprionate (T, 100 mg, twice weekly) or T + the androgen receptor antagonist, flutamide (15 mg/kg BW daily; T+F,) from days 30 to 90 of gestation. Fetal ovaries were collected on d65 (n=4, 5, and 5 for T, T+F, and control [C] groups, respectively) and d90 (n=5, 7, 4) of gestation and snap frozen. Ovarian RNA was subjected to quantitative RT-PCR to measure expression of steroidogenic acute regulatory protein (StAR), cytochrome P450 side chain cleavage (Cyp11A1), cytochrome P450 17α-hydroxylase (Cyp17), cytochrome P450 aromatase (Cyp19), 3-β-hydroxysteroid dehydrogenase (3βHSD), 5α-reductase, androgen receptor (AR), estrogen receptors (ER) α and β, and progesterone receptor (PR). Data were analyzed by 2-way ANOVA followed by Bonferroni post-hoc statistical tests. Maternal T had no effect on AR, PR, ERα and ERβ mRNA expression but levels of ERα and AR mRNA were higher in d90 than d65 ovaries. There was no age effect on steroidogenic enzyme expression in control ovaries. Gestational T excess increased (P<0.05) Cyp19 (3.9-fold) and 5α-reductase (1.8-fold) expression in fetal d65 ovaries but decreased (P<0.05) Cyp11A1 expression (3.7 fold) in d90 ovaries. Maternal T excess had no effect on mRNA expression of other steroidogenic enzymes. Co-treatment with the androgen antagonist, flutamide, prevented the T-induced decrease in Cyp11A1 mRNA seen at d90, but not the increase in Cyp19 and 5α-reductase seen in d65 ovaries. Co-treatment with T+F also increased (P<0.05) StAR (2.0-fold) and Cyp11A1 (3.0-fold) expression in d65 ovaries, compared to C and T-treated ovaries. Our findings suggest that the effects of gestational T treatment on Cyp11A1 is mediated by androgenic actions of T and the effects on Cyp19 and 5α-reductase likely via estrogenic actions stemming from aromatization of T to estrogen and that these changes are fetal age dependent. Increased StAR and Cyp11A1 mRNA expression at d65 in the T+F ovaries, but not the T-alone ovaries, indicates that AR is primarily repressing expression of these two transcripts. Additionally, the increased potential for estrogen metabolism (i.e., increased Cyp19) in the d65 T-alone but not T+F ovaries indicates that estrogenic effects can only be manifest if the AR is blocked. Evidence for estrogenic effect is consistent with our recent finding of increased estradiol levels in the fetal blood of day 65 and 90 T-treated fetuses. These studies demonstrate that maternal T treatment alters fetal ovarian steroidogenic gene expression and implicate direct actions of estrogens in addition to androgens in the reprogramming of fetal developmental trajectory leading up to adult reproductive pathologies. Supported by NIH P01 HD44232 (VP). (platform)

Fetal, infant, adolescent and adult phenotypes of polycystic ovary syndrome in prenatally androgenized female rhesus monkeys

Old World monkeys provide naturally occurring and experimentally induced phenotypes closely resembling the highly prevalent polycystic ovary syndrome (PCOS) in women. In particular, experimentally induced fetal androgen excess in female rhesus monkeys produces a comprehensive adult PCOS-like phenotype that includes both reproductive and metabolic dysfunction found in PCOS women. Such a reliable experimental approach enables the use of the prenatally androgenized (PA) female rhesus monkey model to (1) examine fetal, infant and adolescent antecedents of adult pathophysiology, gaining valuable insight into early phenotypic expression of PCOS, and (2) to understand adult pathophysiology from a mechanistic perspective. Elevated circulating luteinizing hormone (LH) levels are the earliest indication of reproductive dysfunction in late gestation nonhuman primate fetuses and infants exposed to androgen excess during early (late first to second trimester) gestation. Such early gestation-exposed PA infants also are hyperandrogenic, with both LH hypersecretion and hyperandrogenism persisting in early gestation-exposed PA adults. Similarly, subtle metabolic abnormalities appearing in young nonhuman primate infants and adolescents precede the abdominal adiposity, hyperliplidemia and increased incidence of type 2 diabetes that characterize early gestation-exposed PA adults. These new insights into the developmental origins of PCOS, and progression of the pathophysiology from infancy to adulthood, provide opportunities for clinical intervention to ameliorate the PCOS phenotype thus providing a preventive health-care approach to PCOS-related abnormalities. For example, PCOS-like traits in PA monkeys, as in PCOS women, can improve with better insulin-glucose homeostasis, suggesting that lifestyle interventions preventing increased adiposity in adolescent daughters of PCOS mothers also may reduce their risk of acquiring many PCOS-related metabolic abnormalities in adulthood.

Developmental Programming: Impact of Prenatal Testosterone Excess on Pre- and Postnatal Gonadotropin Regulation in Sheep1

The goal of this study was to explore mechanisms that mediate hypersecretion of LH and progressive loss of cyclicity in female sheep exposed during fetal life to excess testosterone. Our working hypothesis was that prenatal testosterone excess, by its androgenic action, amplifies GnRH-induced LH (but not FSH) secretion and, thus, hypersecretion of LH in adulthood, and that this results from altered developmental gene expression of GnRH and estradiol (E2) receptors, gonadotropin subunits, and paracrine factors that differentially regulate LH and FSH synthesis. We observed that, relative to controls, females exposed during fetal life to excess testosterone, as well as the nor-aromatizable androgen dihydrotestosterone, exhibited enhanced LH but not FSH responses to intermittent delivery of GnRH boluses under conditions in which endogenous LH (GnRH) pulses were suppressed. Luteinizing hormone hypersecretion was more evident in adults than in prepubertal females, and it was associated with development of acyclicity. Measurement of pituitary mRNA concentrations revealed that prenatal testosterone excess induced developmental changes in gene expression of pituitary GnRH and E2 receptors and paracrine modulators of LH and FSH synthesis in a manner consistent with subsequent amplification of LH release. Together, this series of studies suggests that prenatal testosterone excess, by its androgenic action, amplifies GnRH-induced LH response, leading to LH hypersecretion and acyclicity in adulthood, and that this programming involves developmental changes in expression of pituitary genes involved in LH and FSH release.

Polycystic ovary syndrome and its developmental origins

The prenatal testosterone (T)-treated adult female rhesus monkey is one animal model of polycystic ovary syndrome (PCOS) in women, with early prenatal T excess programming a permanent PCOS-like phenotype characterized by luteinizing hormone (LH) hypersecretion from reduced hypothalamic sensitivity to steroid negative feedback and relative insulin excess from increased abdominal adiposity. These combined reproductive and metabolic abnormalities are associated with ovarian hyperandrogenism and follicular arrest in adulthood, as well as premature follicle differentiation and impaired embryo development during gonadotropin therapy for in vitro fertilization (IVF). A second animal model for PCOS, the prenatal T-treated sheep also is characterized by LH hypersecretion from reduced hypothalamic sensitivity to steroid negative feedback, persistent follicles and insulin resistance, but also is associated with intrauterine growth retardation and compensatory growth after birth. The ability of prenatal T excess in both species to alter the developmental trajectory of multiple organ systems in utero provides evidence that the hormonal environment of intrauterine life programs target tissue differentiation, raising the possibility that T excess in human fetal development promotes PCOS in adulthood. Such a hypothesis must include data from clinical studies of PCOS women to clarify the homology between these PCOS-like animal models and PCOS per se in reproductive and metabolic function. Future studies should develop new clinical strategies that improve pregnancy outcome and minimize pregnancy loss in women with disorders of insulin action, including PCOS, obesity and diabetes mellitus as well as minimize transgenerational susceptibility to adult PCOS and its metabolic derangements in male close relatives.

Reproductive consequences of polycystic ovarian syndrome

Polycystic ovarian syndrome (PCOS) is a common endocrine disorder affecting women in their reproductive years. It is frequently associated with reproductive dysfunction, including anovulatory infertility and early pregnancy loss. The underlying pathophysiology of PCOS is not fully understood, although there is considerable evidence to suggest that an excess of ovarian androgen production, either genetically determined or due to hyperinsulinaemia or hypersecretion of luteinising hormone (LH), remains central in the pathogenesis of PCOS. Chronic anovulation seems to be the result of abnormal folliculogenesis characterised by follicular arrest at the small antral phase with escape from atresia. Hypersecretion of LH, hyperandrogenaemia and/or hyperinsulinaemia has been postulated as the possible underlying mechanism of early pregnancy loss in women with PCOS. Anovulatory infertility in PCOS women can be treated with insulin-sensitising measures (such as weight reduction and metformin), clomifene citrate, laparoscopic ovarian diathermy (LOD) and ovarian stimulation with follicle-stimulating hormone. LOD and metformin may help to reduce the risk of miscarriage in women with PCOS, although the effectiveness of these measures remains to be established.

Polycystic ovary syndrome and gynecological cancers: Is there a link?

Polycystic ovary syndrome [PCOS] is the most common endocrinopathy of women in reproductive age. An association between PCOS and type-1 endometrial cancer has often been reported in the literature. The prolonged anovulation with consequent continued secretion of estrogen unopposed by progesterone may enhance the development and growth of this malignancy, particularly in young women. Hypersecretion of luteinizing hormone [LH], chronic hyperinsulinemia and increased serum insulin-like growth factor [IGF]-I levels may represent risk factors for endometrial cancer. However, data available in the literature do not allow a meta-analysis to be carried out to calculate an estimate of the relative risk of endometrial cancer in women with PCOS. Anecdotal cases of low-grade endometrial stromal sarcoma and carcinosarcoma have been reported in association with prolonged unopposed estrogen stimulation, and in particular with PCOS. A few studies have addressed the possibility of an association between PCOS and epithelial ovarian cancer risk, and the results are conflicting but generally reassuring, and similarly the few available data appear to exclude a strong association between PCOS and breast cancer.

Effects of insulin on luteinizing hormone and prolactin secretion and calcium signaling in female rat pituitary cells.

Polycystic ovary syndrome (PCOS) is associated with insulin resistance and hyperinsulinemia, which might contribute to the hypersecretion of luteinizing hormone (LH). Hyperprolactinemia is another finding in a subgroup of patients with PCOS, whereas its relation to hyperinsulinemia is not fully understood yet. In the present study we tested the hypothesis that insulin might affect LH or prolactin secretion of cultured female rat pituitary cells. To address the mechanisms by which insulin could act at the intracellular level we examined the GnRH- and TRH-induced Ca(2+) signals in single gonadotrophs and lactotrophs, because Ca(2+) is an important component of GnRH signal transduction that is closely related to exocytosis. Cells treated for 24 h with insulin (10(-9) M) showed an enhancement of basal and agonist-induced LH and prolactin secretion. Insulin did not affect GnRH- and TRH-induced Ca(2+) signals compared to controls. There were no differences neither in the frequency nor in the amplitude of the Ca signal. Our findings suggest that insulin might contribute to LH hypersecretion. Insulin might be partially responsible for hyperprolactinemia. Since insulin did not affect Ca signaling, other components of the GnRH signal transduction pathway might be involved in LH hypersecretion.

Central infusion of recombinant ovine leptin normalizes plasma insulin and stimulates a novel hypersecretion of luteinizing hormone after short-term fasting in mature beef cows.

The present studies tested the hypotheses that short-term fasting would reduce leptin gene expression and circulating concentrations of leptin and insulin in mature, ovariectomized, estradiol-implanted cows and that intracerebroventricular infusions of recombinant ovine leptin (oleptin) would attenuate reductions in insulin concentration and stimulate LH secretion. Ovariectomized cows were assigned to either control (normal fed; n = 6) or fasted (60 h of fasting; n = 7) groups and infused with 200 microg recombinant oleptin three times at hourly intervals on Day 2 (n = 6 per group). Fasting decreased plasma concentrations of insulin (P < 0.01) and leptin (P < 0.04) but, as expected, did not reduce plasma concentrations of glucose or any LH secretion variable. Central infusion of leptin on Day 2 increased (P < 0.01) plasma concentrations of leptin in both control and fasted groups. Concomitantly, leptin treatment increased plasma insulin (P < 0.01) and LH (P < 0.03) concentrations in fasted but not in control cows. Increases in overall mean and baseline concentrations of LH after leptin treatment were the result of an augmentation of the size of LH pulses. The effects of fasting on leptin gene expression and the potential diurnal effects on circulating leptin were examined in a group of cows (n = 12) not treated with leptin. Fasting for 60 h reduced (P < 0.001) leptin gene expression by 30%, and no diurnal effects on circulating leptin were observed. These results indicate that although short-term fasting does not reduce the frequency or amplitude of LH pulses or the concentration of LH in mature cows, this nutritional perturbation clearly sensitizes both the hypothalamic-pituitary axis and endocrine pancreas to exogenous leptin, which in these experiments resulted in heightened secretion of both LH and insulin.

Interaction between luteinizing hormone (LH) and insulin (I) during gonadotropin stimulation for in vitro fertilization (IVF) affects intrafollicular steroidogenesis in prenatally androgenized female rhesus monkeys.

Objective: Adult female rhesus monkeys exposed to prenatal androgen excess during the first third of pregnancy demonstrate LH hypersecretion, abnormal I responsiveness to infused glucose (GLU) and impaired blastocyst development. This relationship between circulating LH and I abnormalities and blastocyst development may involve disordered ovarian steroidogenesis since cultured human granulosa cells pretreated with (I) demonstrate exaggerated LH-induced P4 production. This study examines serum LH and I levels in prenatally androgenized (PA) female monkeys undergoing gonadotropin therapy for IVF to determine whether abnormal LH or I secretion affects intrafollicular progesterone (P4) and estradiol (E2) concentrations.

Bilateral or Unilateral KTP Laser Ovarian Drilling in Polycystic Ovarian Disease

Bilateral or Unilateral KTP Laser Ovarian Drilling in Polycystic Ovarian Disease

Effects of orchidectomy on levels of the mRNAs encoding gonadotropin-releasing hormone and other hypothalamic peptides in the adult male rhesus monkey (Macaca mulatta).

The testicular regulation of luteinizing hormone (LH) secretion in the adult rhesus monkey is mediated by an indirect action of testosterone to decelerate pulsatile gonadotrophin releasing hormone (GnRH) release. Whether this negative feedback action of testosterone involves regulation of GnRH gene expression is unknown. Therefore, the effect of bilateral orchidectomy on hypothalamic levels of the mRNA encoding this hypophysiotropic factor was examined. The feedback action of testosterone is generally considered to be mediated through non-GnRH cells, and the present experiment provided the opportunity to also examine testicular influences on mRNAs encoding putative hypothalamic factors implicated in the testicular regulation of LH secretion. Adult male rhesus monkeys were orchidectomized (n=5) or sham-orchidectomized (n=5) and killed 6 weeks later, after a castration-induced hypersecretion of LH was established. Separate preoptic and mediobasal hypothalamus containing areas were collected, and levels of GnRH mRNA, as well as those of mRNAs encoding pro-opiomelanocortin (POMC), the gamma-aminobutyric acid (GABA) synthesizing enzymes (glutamic acid decarboxylase 65 and 67; GAD65 and GAD67, respectively), neuropeptide Y, galanin and transforming growth factor (TGF)alpha, were quantified using RNase protection assay. Values were expressed in terms of optical density relative to that of cyclophilin mRNA levels. Bilateral orchidectomy produced a significant increase in GnRH mRNA levels that was restricted to the mediobasal hypothalamus and that was associated with a significant decrease in POMC, GAD65 and GAD67 mRNA levels in this region of the hypothalamus. In contrast, neuropeptide Y, galanin and TGFalpha mRNA levels were not affected by castration. These results indicate that, in the monkey, the deceleration of pulsatile GnRH release that is imposed by the testis, and presumably mediated by testosterone, is associated with a concomitant down regulation of GnRH gene expression in the mediobasal hypothalamus. They also support the notion that this hypothalamic feedback action may be mediated by POMC-and GABA-producing neurones in the mediobasal hypothalamus.