PRESENCE OF POSITIVE FEEDBACK BETWEEN OESTROGEN AND LH IN PATIENTS WITH KLINEFELTER'S SYNDROME, AND SERTOLI-CELL-ONLY SYNDROME

Abstract

In 5 adult patients with Klinefelter''s syndrome and 2 with Sertoli-cell only syndrome, exogenous administration of 17.beta.-estradiol, resulting in a sustained and prolonged elevation of circulating estrogen levels, had a biphasic effect on LH [luteinizing hormone] release. After an initial decrease, a dramatic rise in peripheral levels of LH (positive feedback) was observed in all patients. The timing and magnitude of the induced LH surge was similar to that observed in postmenopausal women after administration of large doses of ethinylestradiol. A similar positive feedback effect on the secretion of FSH [follicle stimulating hormone] could not be demonstrated. In 2 patients with the Sertoli-cell-only syndrome, estrogen treatment induced marked variations in serum testosterone levels, which appeared to be related to the LH changes. Similar changes were not present in patients with Klinefelter''s syndrome, indicating a decrease in the sensitivity of the testicular Leydig cell. Positive feedback between estrogen and luteinizing hormone is present in the adult human male.