Sex-specific proteins in normal chick embryo gonads and testis feminized by oestrogen treatment: a two-dimensional gel electrophoresis investigation.

Gonads dissected from 17-day-old normal chick embryos, as well as testes feminized by oestrogen treatment, were labelled in vitro with [35S]methionine and [14C]leucine. The patterns of cytosolic protein synthesis by the gonads were analysed using two-dimensional (2-D) polyacrylamide gel electrophoresis. In the feminized testis, two female-specific proteins appeared, the rate of synthesis of four testis-specific proteins was decreased, and quantitative variations of other synthesized proteins in relation to sex were detected. This altered protein synthesis indicates that the protein synthesis of the testis feminized by oestrogen treatment has in part become similar to that of a normal ovary. The synthesis of female-specific proteins in the feminized testis raises the question of their role in normal ovarian differentiation.