BIOSYNTHESIS OF STEROIDS BY GONADS OF RICEFIELD EEL MONOPTERUS ALBUS AT VARIOUS PHASES DURING NATURAL SEX REVERSAL

The in vitro steroid biosynthetic capacity of the gonads of Monopterus albus, a protogynous hermaphroditic teleost, was studied by incubating the gonadal tissue with tritiated pregnenolone at various stages during sex reversal. The incubations were analyzed for steroids by thin-layer chromatography, isotope dilution, and derivative formation techniques, and the radioactive products included progesterone, 17αOH-progesterone, androstenedione, testosterone, estradiol-17β, and estrone in addition to a number of unknown polar metabolites. Steroids produced by the gonads at various sexual phases were the same qualitatively, but the major sex steroids showed a shift in their production during sex reversal so that comparatively more estrogens were produced by the females, and, when structural transformation from ovary to testis commenced, androgen production increased markedly. The increase in androgen production appeared to be related to the development of the interstitial Leydig cells during the reversal of sex. © 1969.