The acute effects of a dopamine antagonist (domperidone) on luteinising hormone, follicule stimulating hormone, prolactin and thyrotrophin secretion in polycystic ovarian syndrome: differential effect of ovulation

Association between prolactin receptor expression and proliferation in the endometrium of obese women with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is associated with increased risk of endometrial cancer. There is growing evidence that prolactin and its receptor (PRLR) are involved in the development of cancer. We assessed endometrial expression of PRLR mRNA, and immunostaining of PRLR and the proliferation marker Ki67 on different cycle days in obese (OB-PCOS) and normal-weight women with PCOS and body mass index-matched controls. The OB-PCOS group underwent a 3 months lifestyle intervention. Prior to intervention, obese women with PCOS and controls had lower endometrial levels of PRLR mRNA in proliferative endometrium than the normal-weight groups (p < .05). After intervention, six OB-PCOS women had confirmed ovulation, while 12 remained anovulatory. Both these subgroups displayed higher immunostaining of PRLR in endometrial stroma, and in the anovulatory subgroup also increased Ki67, on cycle days 21-23 compared with controls (p < .05). In obese controls, the PRLR mRNA expression was decreased in secretory endometrium compared with proliferative endometrium (p = .004). A corresponding change within the cycle was not found in OB-PCOS women. Immunostaining of PRLR in the secretory phase correlated positively with Ki67 (p < .05) in the endometrium. These observations suggest that short-term lifestyle intervention can restore ovulation but not normalize PRLR expression in the endometrium of obese women with PCOS. Trial registration: ISRCTN, ISRCTN18400086, https://doi.org/10.1186/ISRCTN18400086.

Preliminary results suggesting exaggerated ovarian androgen production early in the course of polycystic ovary syndrome

Excess ovarian androgen production might be a cause of the polycystic ovary syndrome (PCO). Previous studies have evaluated adult women with long-standing abnormality of the hypothalamic-pituitary gonadal axis. Abnormal ovarian function in such patients could be a primary or even a secondary finding. For that reason, this study was designed to evaluate ovarian androgen production in symptomatic adolescent females. Simultaneous adrenal suppression, by using dexamethasone, and ovarian stimulation, by using gonadotropin-releasing hormone (GnRH), were achieved in 12 patients. Following stimulation, blood was serially obtained over 8 hr to measure gonadotropin, estrogen, and androgen responses. Based on the androgen response, patients could be divided into two groups. Group A (five) had a significant increase (p less than 0.01) in free testosterone, whereas group B (seven) had no increase in any androgen, including free testosterone (significantly different from group A, p = 0.01). All patients in group A had enlarged or cystic ovaries, whereas only one-quarter patients in group B had enlarged ovaries (significantly different from group A, p less than 0.03). The pituitary and estrogenic response was similar in both groups. These preliminary data suggest that some patients with PCO (group A) have a primary abnormality in ovarian androgen production early in the course of their disease.

Evidence for mutually antagonistic actions of thyroid releasing hormone and inhibin at pituitary-gonadal-prostate-spermatozoal axis

In-vivo as well as in-vitro studies carried out demonstrate for the first time the interaction between thyroid releasing hormone (TRH) and inhibin at the pituitary, testes, prostate and spermatozoa levels. At the pituitary level both peptides act as antagonists to each other and modify the release of pituitary hormones. Further, these peptides act at the prostatic level wherein they modulate ornithine decarboxylase activity as well as 5 alpha-reductase activity. At the testicular level TRH blocks inhibin biosynthesis whereas in semen, it significantly reduces the binding of spermatozoa to specific antibodies directed against inhibin. In conclusion, although TRH and inhibin are widely different in their molecular size and chemical structure, these peptides seems to act antagonistically at multiple sites.

Treatment of hirsutism in polycystic ovary syndrome with bromocriptine

The value of bromocriptine in the treatment of hirsutism in polycystic ovary syndrome (PCO) was assessed subjectively and photographically in a double-blind trial in 22 women studied for 1 year. Menstrual frequency was recorded. Circulating concentrations of oestradiol, oestrone, testosterone, androstenedione, and sex hormone binding globulin (SHBG) were determined before treatment and after 6 and 12 months therapy. On the same occasions gonadotrophin concentrations (mean of 24 samples) and their response to 100 micrograms LHRH were determined. No evidence was found to support a therapeutic role for bromocriptine in the treatment of hirsutism or menstrual regulation in PCO. No biochemical changes were seen specific to bromocriptine therapy.

Studies of prolactin secretion in polycystic ovary syndrome

In order to investigate the postulated relationship between hyperprolactinaemia and polycystic ovary syndrome (PCOS) we have studied 62 patients with PCOS. Only two patients had persistent prolactin (PRL) concentrations greater than the normal range on both random sampling and after blood sampling from intravenous cannula over 2 hours. Twenty-eight of the remaining patients had basal PRL secretion studied in more detail. Samples were collected at 15 min intervals during a 6 h period in all 28 patients and hourly samples were collected overnight from four patients. Results failed to demonstrate differences from control subjects in mean basal PRL concentrations, in spontaneous fluctuations or in increments related to stress, food or sleep. Lactotroph response to thyrotrophin releasing hormone, luteinising hormone releasing hormone and insulin stress testing in PCOS were determined. Results confirm a previous observation that normal PRL increments occur after ovulation and a blunted response follows a period of anovulation. This study has failed to find a consistent abnormality of lactotroph function in patients with PCOS other than that associated with anovulation.