Inter- and Intraspecific Variation in Sex Hormone-Induced Sex-Reversal in Medaka, Oryzias latipes and Oryzias sakaizumii

We compared sex-reversal ratios induced by 17α-methyltestosterone (MT) and 17β-estradiol (E2) exposure in two inbred medaka strains: Hd-rR derived from Oryzias latipes and HNI-II from O. sakaizumii. All MT exposures (0.2–25 ng mL–1) induced complete XX sex-reversal in HNI-II. Although MT exposure at 0.2 ng mL–1 induced XX sex-reversal at > 95% in Hd-rR, other concentrations tested caused XX sex-reversal at lower frequencies (<50%). MT exposure...