INTERCONVERSION AND AROMATIZATION OF ANDROGENS BY HUMAN ADIPOSE-TISSUE

Incubations were carried out to study the interconversion and aromatization of androstenedione and testosterone in human adipose tissue. In abdominal and omental fat using androstenedione at a variety of substrate concentrations, testosterone was isolated from all incubations, estrone from 8 out of 12 incubations and estradiol from 3 out of 12 incubations. Using breast adipose tissue from male and female subjects, testosterone, estrone and estradiol were isolated from all incubations. No consistent difference in the capacity of adipose tissue to aromatize androstenedione was noted in adipose tissue from different sources. In studies on isolated fat cells and the fibrovascular stroma of adipose tissue the interconversion of testosterone and androstenedione was demonstrated in both tissues. Human adipocyte precursors isolated from the stromal-vascular fraction of human omental adipose tissue converted androstenedione to testosterone and estrone. These studies confirm the aromatization of androstenedione in adipose tissue from a variety of sources. Androgens are evidently interconverted in adipose tissue and the net effect of a gonadal steroid acting on a peripheral tissue may depend on the nature of the metabolites formed in that tissue.