Immortalized GnRH neurons (GT1-7) express receptors for estrogen [estrogen receptor-alpha and -beta(ERalpha and ERbeta)] and progesterone (progesterone receptor A) and exhibit positive immunostaining for both intracellular and plasma membrane ERs. Exposure of GT1-7 cells to picomolar estradiol concentrations for 5-60 min caused rapid, sustained, and dose-dependent inhibition of cAMP production. In contrast, treatment with nanomolar estradiol concentrations for 60 min increased cAMP production. The inhibitory and stimulatory actions of estradiol on cAMP formation were abolished by the ER antagonist, ICI 182,780. The estradiol-induced inhibition of cAMP production was prevented by treatment with pertussis toxin, consistent with coupling of the plasma membrane ER to an inhibitory G protein. Coimmunoprecipitation studies demonstrated an estradiol-regulated stimulatory interaction between ERalpha and Galphai3 that was prevented by the ER antagonist, ICI 182,780. Exposure of perifused GT1-7 cells and hypothalamic neurons to picomolar estradiol levels increased the GnRH peak interval, shortened peak duration, and increased peak amplitude. These findings indicate that occupancy of the plasma membrane-associated ERs expressed in GT1-7 neurons by physiological estradiol levels causes activation of a Gi protein and modulates cAMP signaling and neuropeptide secretion.

Background Autonomous ovarian activation with recurrent estrogen-producing cysts is a hallmark feature of the rare bone and endocrine disorder fibrous dysplasia/McCune-Albright syndrome. Precocious puberty in girls with McCune-Albright syndrome has been well-described, however long-term effects on gynecologic and reproductive function are unknown. Concerningly, case reports have described poor skeletal outcomes associated with pregnancy in women with fibrous dysplasia. Methods Thirty-nine women with fibrous dysplasia/McCune-Albright syndrome were evaluated as part of a natural history study. Clinical, radiographic, and biochemical data were reviewed. Women were contacted to obtain detailed menstrual and reproductive histories. Results Abnormal uterine bleeding affected 77% of women (30/39), and was associated with severe anemia requiring blood transfusion in 3 cases. Nine women underwent hysterectomy for management of bleeding, including 67% (6/9) at the unusually young age of less than age 35 years. Infertility affected 43% of women (9/21), including 2 women who developed primary ovarian insufficiency after undergoing surgical treatment of ovarian cysts. Of 25 spontaneous pregnancies in 14 women, 35% (8) were unplanned. Among the 14 pregnancies, pregnancy was associated with no change in bone pain in 7 subjects (53%), increased bone pain in 4 subjects (31%), and decreased bone pain in 2 subjects (15%). No additional skeletal complications were reported during pregnancies. Conclusions Women with fibrous dysplasia/McCune-Albright syndrome report a high prevalence of gynecologic morbidity and reduced fertility. There is no clear association between pregnancy and poor skeletal outcomes in this population.

Isolated FSH deficiency due to a mutation in the FSHbeta subunit is characterized by an extremely low serum FSH concentration. We report a patient who presented with an FSH of 0.8 mIU/ml and infertility associated with anovulation. Endocrinological assessment and immunohistochemistry revealed that a granulosa cell tumour was secreting inhibin B and suppressing FSH; however, LH and estradiol were within their normal ranges. Upon removal of the tumour, inhibin B decreased and FSH levels rose to normal values. The patient subsequently conceived and delivered successfully. Based on this case and on those previously described in the literature, we suggest that inhibin B levels should be evaluated in anovulatory patients having a clinical presentation consistent with functional hypothalamic amenorrhoea and very low to normal values of FSH.