Effects on the endocrine system oflong-term treatment with the luteinizing hormone-releasing hormone agonist leuprolide in patients with benign prostatic hyperplasia

Hormonal changes resulting from long-term use of the luteinizing hormone-releasing hormone agonist leuprolide depot were studied in a randomized placebo-controlled study comprising 50 evaluable patients with benign prostatic hyperplasia (BPH). A total of 26 patients received 3.75 mg leuprolide depot intramuscularly every 28 days for 24 weeks and 24 received a placebo. The patients were followed up for a further 24-week period. Serum concentrations of luteinizing hormone decreased by 90% and follicle-stimulating hormone by 55% during the treatment period. Mean testosterone levels decreased by 96% to 0.7 nmol l(-1) and dihydrotestosterone decreased by 90%. The adrenal androgens androstenedione and dehydroepiandrosterone sulphate decreased by 48 and 24%, respectively. In most patients, estradiol decreased to non-detectable values, while the decrease in estrone was 35%. There was no change in prolactin and sex hormone-binding globulin as compared to the placebo group. Hormonal changes were reversible, but the suppression of testicular hormone production was not completely normalized in all patients 24 weeks after discontinuation of the treatment.