Androgen and estrogen production in elderly men with gynecomastia and testicular atrophy after mumps orchitis.

Gynecomastia developed in three men 1-30 yr after the occurrence of testicular atrophy due to mumps orchitis. At the time of study, these men were 63-68 yr of age. In these men the mean plasma production rate of testosterone was 816 microgram/24 h, a value 20% of that found in normal elderly men without gynecomastia. The plasma production rate of androstenedione averaged 1317 microgram/24 h. The mean production rates of 17 beta-estradiol and estrone in these subjects were 33 and 48 microgram/24 h, values comparable to those of normal young men. Extraglandular formation of estrogen from plasma prehormones accounted for all of the 17 beta-estridiol and most of the estrone produced by these elderly men with gynecomastia. Serum gonadotropin concentrations were elevated in these men, probably because plasma testosterone production rates were decreased. These findings are consistent with the view that the capacity of Leydig cells to secrete testosterone was impaired after mumps orchitis in these subjects, but the capacity to form estrogen was not similarly impaired, since most estrogen is formed in extraglandular sites. Thus, the impairment in Leydig cell testosterone secretion after mumps orchitis together with the normal increase in extraglandular aromatization that accompanies aging bring about a striking reduction in the ratio of testosterone to estrogen production rates, and gynecomastia may result.