Androgen receptors in two androgen-mediated, sexually dimorphic charactersof frogs

The presence/absence of androgen receptors is examined in two sexually dimo rphic features of frogs: the nuptial pad and the external oblique muscle. I mmunohistochemistry reveals that both males and females possess andro gen r eceptors in these tissues. Males have a higher density of immunopositive nu clei in the oblique muscle than do females. The presence of androgen recept ors in both male and female tissues is consistent with results from hormone experiments in which androgen supplements induce the expression of a nupti al pad and enlarge the external oblique muscles in castrated males and ovar iectomized females. (C) 1999 Academic Press.