Patterns of serum FSH, LH and hCG after i.m. or i.v. administration of hMG during pituitary suppression.

OBJECTIVE -- The study was undertaken to investigate the effects of a commonly used ovarian stimulation regimen on gonadotropin levels. METHODS -- The behavior of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and human chorionic gonadotropin (hCG) was studied after intramuscular (i.m.) and intravenous (i.v.) human menopausal gonadotropin (hMG) administration. Six female volunteers participated in the study. During pituitary suppression with a gonadotropin-releasing hormone (GnRH) agonist (Buserelin), a single dose of hMG (150 IU) was injected i.m. or i.v., in a cross-over design with an interval of 2 weeks. Blood samples were collected frequently after the injection. Serum concentrations of FSH, specific LH and hCG were determined. RESULTS -- After i.m. administration of hMG, a peak FSH concentration of 7.4 +/- 1.3 U/L was reached after 8 (6-24) hours, with a subsequent decrease. At 0.5 hour after i.v. administration, peak FSH values of 30.5 +/- 5.6 U/L were obtained, followed by a decrease to baseline levels within 48 hours. Exogenous LH and hCG were hardly detectable after i.m. administration of hMG. One-half hour after i.v. injection of hMG, a small increase in specific LH levels to 6.7 +/- 2.6 U/L was shown, followed by a decline. hCG concentrations increased after i.v. hMG administration to 7.6 +/- 1.6 U/L.