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.