Effect of follicle stimulating hormone treatment on the pituitary response to luteinizing hormone-releasing hormone in post-menopausal women

To study the role of exogenous follicle stimulating hormone(FSH) in the attenuation of luteinizing hormone (LH) responseto luteinizing hormone-releasing hormone (LHRH) during ovulationinduction in women, 10 healthy post-menopausal women were treatedwith FSH (225 IU/day) for 5 days and normal saline (2 ml/day)for another 5 days. The two regimens were given consecutivelyin a 10 day experiment. The regimen for the first 5 days wasrandomly chosen and was given to the women in an alternate way.The response of LH to an i.v. injection of 10 µg LHRHwas investigated twice on day 1 (i.e. before the onset of treatmentand 12 h later) and once on days 2, 5 and 10 of the experiment(0900 h). Basal FSH and LH values before the onset of treatmenton day 1 were similar in the five women who started with thesaline and the five who started with the FSH regimen. BasalFSH values increased significantly during treatment with FSH,while LH and oestradiol values remained unchanged throught thewhole experiment. LH increment 30 min post –LHRH did notchange significantly either during the first 24 h or duringthe whole experiment regardless of the starting regimen. Theseresults demonstrate that in post-menopausal women the responseof LH to LHRH is not affected by exogenous administration ofFSH. It is suggested that exogenous FSH does not show activitieson gonadotrophin secretion similar to those ascribed to a gonadotrophinsecretion similar to those ascribed to a gonadotrophin surgeattenuating factor.