Androgens are powerful agents affecting and for manipulating
sex determination in fishes [14]. This is also true in sex-changing
species. Reinboth and Becker [67] examined testosterone conversion
by the gonads in the Mediterranean wrasse Coris julis and
showed higher production of 11-hydroxylated androgens in secondary
males. The greater production of 11-KT by the testes of TP
male saddleback wrasses is also consistent with this finding as TP
males showgreater immunoreactivity for 11-hydroxylase, the key
enzyme in 11-KT synthesis (reviewed in [60]). Relatively littlework
has yet addressed steroid receptor levels, although Kim et al. [37]
did show that androgen receptor levels were higher in the brain of
terminal phase males of the threespot wrasse Halichoeres trimaculatus.
Furtherwork in this area is likely to be especially informative.