The early hormonal changes that lead to follicular maturation and/or hyperstimulation in women requiring ovulation induction with either
human menopausal gonadotropin or
gonadotropin-releasing hormone have not been elucidated. This study was undertaken to assess the relative contribution of
follicle-stimulating hormone and
luteinizing hormone to
estradiol secretion and follicular maturation in patients receiving
human menopausal gonadotropin or
gonadotropin-releasing hormone. The study group consisted of 10 women (26 to 38 years of age) with secondary
amenorrhea as a result of hypothalamic dysfunction who had failed to ovulate when given
clomiphene citrate. The patients were randomly assigned to either
human menopausal gonadotropin (n = 5) or
gonadotropin-releasing hormone (n = 5) treatment. On day 5 after the onset of induced menses, all women had baseline blood samples obtained at 10-minute intervals for 4 hours. At this time either 150 U of
human menopausal gonadotropin or 75 ng/kg of
gonadotropin-releasing hormone administered hourly was given, and blood sampling every 10 minutes was continued for an additional 6 hours. Thereafter, patients were evaluated daily until ovulation. A significant and sustained increase in the mean plasma
follicle-stimulating hormone level was first measured during the third hour after
human menopausal gonadotropin administration (p less than 0.05. The area under the curve of the mean plasma
follicle-stimulating hormone value after this initial increase was significantly greater than its baseline (2119 +/- 240 versus 1425 +/- 188 mlU/ml; p less than 0.01). This rise in mean
follicle-stimulating hormone level was followed in less than 2 hours by a significant and uniform rise in mean plasma
estradiol concentration (p less than 0.05). In contrast, no immediate change in the mean levels of
luteinizing hormone,
follicle-stimulating hormone, or
estradiol occurred after
gonadotropin-releasing hormone administration. The mean daily levels of
luteinizing hormone were similar in both groups; however, mean daily
follicle-stimulating hormone (20.0 +/- 1.1 versus 9.2 +/- 1.4 mlU/ml) and
estradiol (1004 +/- 174 versus 495 +/- 83 pg/ml) levels were significantly higher in patients treated with
human menopausal gonadotropin than in those treated with
gonadotropin-releasing hormone (p less than 0.001 and p less than 0.05, respectively). In addition, only in patients receiving
human menopausal gonadotropin was a positive correlation found between mean daily plasma
estradiol and
follicle-stimulating hormone (r = 0.685, p less than 0.05) levels and between mean daily plasma
estradiol and
prolactin (r = 0.94, p less than 0.001) levels.(ABSTRACT TRUNCATED AT 400 WORDS)