[Growth and development of pre-implantation rat embryos in vitro. Effect of various hormonal factors].

The effect of 17 beta-estradiol and polypeptides of hypophyseal origin (prolactin, adenohypophysis cell culture secretion products) on the development of 5-day rat embryos in vitro was studied. Preimplantation rat embryos grew and developed normally in medium 199 enriched with 10% embryonic calf serum. The addition into this medium of estradiol in the concentrations of 10(-6) M, 10(-8) M or prolactin (0.01 micrograms/ml) did not produce an injuring effect on the growth of embryos incubated in vitro. A clear embryotoxic effect was noted in the incubation of embryos in a medium with high concentrations (0.1-1 microgram/ml) of prolactin or in a 3-day culture of rat adenohypophyseal cells. It may be inferred that the inhibitory effect of high doses of prolactin on embryo development is one of the possible causes of the embryotoxic effect of adenohypophysis cell culture secretion products.