Measurement of androgen and estrogen receptors in breast tissue from subjects with anabolic steroid-dependent gynecomastia.

In order to assess the relationship between anabolic steroid administration and gynecomastia, we studied the effects produced by administering nandrolone decanoate and a mixture of propionate, phenilpropionate, isocaproate and testosterone decanoate to bodybuilders during a six month period. The following significant changes occurred: a 53% reduction in serum testosterone; LH and FSH levels were suppressed to 77% and 87%, respectively, in comparison to control values; and although 45% of the subjects showed an increase in serum estradiol levels, no statistically significant differences were found compared with control estradiol levels. With regard to estradiol and androgen receptors, 85% of gynecomastia tissue contained estradiol or androgen receptors, while 40% contained both. The mean values of estradiol and androgen receptors in the cytosol were 65 +/- 10 and 52 +/- 5 fmol/mg protein, respectively. Nuclear androgen and estradiol receptor levels were 33 +/- 7 and 67.5 +/- 9 fmol/mg protein, respectively. The presence of hormone receptors in gynecomastia receptive cells provides support for the hypothesis that gynecomastia is steroid-dependent.