INHIBITORY EFFECTS ON GONADOTROPHIN SECRETION AND GONADAL FUNCTION IN MEN DURING CHRONIC TREATMENT WITH A POTENT STIMULATORY LUTEINIZING HORMONE-RELEASING HORMONE ANALOGUE

Abstract

Long-term treatment with the potent and long-acting stimulatory luteinizing hormone-releasing hormone (LH-RH) analog D-Ser(TBU)6-EA10-LH-RH was given to 4 healthy men to study its effects on pituitary gonadotropin secretion and gonadal function. LH-RH agonist (5 .mu.g) was self-administered s.c. once daily over 17 wk. Weekly basal blood samples were obtained for determination of follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL) and testosterone. The gonadotropin responses to the LH-RH analog were also determined during the treatment period. LH-RH tests were performed after treatment. Seminal fluid specimens were collected during and after treatment. A reduction of the basal serum gonadotropin and testosterone levels were observed during the treatment period. The FSH and LH responses to the analog were also diminished. After discontinuation of treatment the gonadotropin and testosterone concentrations returned to pretreatment levels within a week. The PRL levels and the seminal fluid specimens did not show any significant changes during the study period. Chronic treatment with D-Ser(TBU)6-EA10-LH-RH has an inhibitory effect on the pituitary gonadotrophin secretion in healthy men. The reduced testosterone level is probably secondary to the diminished gonadotropin secretion.