[Radioactivity distribution in the subcellular fractions of reproductive tract and skeletal muscle tissue in rat and rabbit embryos after in vitro exposure to 1 alpha, 2 alpha-3H(p)-testosterone and 5 alpha-dihydro-1 alpha, 2 alpha(p)-testosterone].

In the in vitro experiments the distribution of radioactivity was studied in the subcellular fractions of the reproductive system and muscles of the rat embryos on the 14-, 16- and 18th days and of the rabbit embryos on the 18th and 20-22nd days of development after the preincubation in the medium with 1 alpha, 2 alpha-3H(n)-testosterone (T-3H). The total consumption of T-3H per mg of tissue is higher in the reproductive system than in the muscles and attains the maximum in the rabbit on the 21st and in the rat on the 18th day of development. The ratio of radioactivity in the nuclear and cytoplasmic fractions per mg of protein changes at the critical period of somatic sex differentiation: in the rabbit between the 20th and 21st and in the rat between the 16th and 18th days of development. The radioactivity in the nuclear fraction is markedly higher than in the cytoplasmic one on the 21st day in the rabbit and on the 18th day in the rat and, on the contrary, lower at all preceding times. The radioactivity in the microsomal fraction is higher than in the cytosol. The distribution of radioactivity of 5 alpha-dihydro-1 alpha, 2 alpha(n)-testosterone (DHT-3H) was studied on the 20th and 21st days of development in the rabbit embryos. No changes in the nucleocytoplasmic ratio of radioactivity was found, but the radioactivity decreased in all fractions on the 21st day.