Switch brain sexuality with steroid hormones!

OK, so it is actually a fish doing it. But, Remage-Healey and Bass suggest that their findings may help explain the widespread distribution of rapidly induced intrasexual behavioral phenotypes among vertebrates in general. They observe that the male acoustic sexual behavior of the teleost type I male midshipman can be rapidly (~ 5 min) induced in type II males (that normally show female like behaviors) by the action of the androgen 11-ketotestosterone on receptors in the brain's vocal pattern generator. (11-ketotestosterone is the dominant circulating androgen in type I males, and testosterone is the dominant androgen in type II males and females). This suggests that steroid-dependent expression of "maleness" and "femaleness" may now include rapid steroid actions on the neurophysiological patterning of behavior, uncoupled from gonadal phenotype.