CHARACTERIZATION OF PENILE ANDROGEN RECEPTOR EXPRESSION IN MICROPENISDUE TO HYPOGONADOTROPIC HYPOGONADISM

Purpose: The recommendation to treat micropenis with. androgen early i n infancy and childhood is based on the fact that the normal penile an drogen receptor decreases in concentration 2 to 3-fold in early adulth ood. Hypothetically the early administration of androgen takes advanta ge of elevated penile androgen receptor concentration, resulting in op timal penile growth. We verify that there are similar patterns of andr ogen receptor expression in micropenis and the normal penis. Materials and Methods: We used a strain of mice with micropenis due to congenit al hypogonadotropic hypogonadism (HPG). Affected mice and normal contr ols were sacrificed before puberty, and during puberty and early and l ate adulthood (15, 30, 60 and 90 days, respectively). At autopsy the p enis was removed, weighed, pooled and processed for protein extraction . Androgen receptor concentration was determined by Western blot analy sis. Results: In controls penile androgen receptor expression increase d 2-fold from before puberty (0.49 fmol./mu g. protein) to puberty (0. 92 fmol./mu g.). At adulthood a S-fold decrease in penile androgen rec eptor occurred with the receptor decreasing to 0.33 fmol./mu g. in ear ly adulthood and 0.27 fmol./mu g. in late adulthood. In HPG animals th e penile androgen receptor concentration increased throughout developm ent from 0.20 fmol./mu g. before puberty 0.33 fmol./mu g, in adulthood . Conclusions: Androgen receptor expression in the microphallic HPG pe nis does not mimic normal developmental penile androgen receptor expre ssion. It remains to be elucidated whether hormonal therapy reverses t hese deficiencies.