Summary
In order to investigate the regulatory mechanisms involved in the secretion of glycoprotein
hormones, we studied the secretory patterns of LH, FSH and alpha-subunit in hypogonadal
men. Three groups of patients with carcinoma of the prostate were studied both before
and 15 days after orchiectomy, or the initiation of ketoconazole or LHRH analog therapy.
There were significant increases (P < 0.01) in LH and alpha-subunit levels in the
patients treated with orchiectomy and ketoconazole, but FSH levels increased only
in the orchiectomized patients. After LHRH analog treatment, LH levels were significantly
decreased when assayed with an immunoradiometric assay method which does not cross-react
with alpha-subunit. FSH values were significantly lower than pretreatment levels,
while alpha-subunit levels remained significantly elevated throughout the study period.
These results demonstrate that after both chemical (ketoconazole) and surgical castration,
the secretion of alpha subunit follows a pattern which is tightly correlated with
that of LH but not of FSH. However, after LHRH analog treatment, alpha-subunit appears
to be the sole secretory product of the gonadotroph.
Key words
LH - FSH - Alpha-Subunit - Castration - LHRH-Analog - Ketoconazole
