[Effect of a number of metabolic inhibitors and other biologically active substances on the development of sea urchin embryos].

Benzo(a)pyrene, hydrocortisone, corticosterone, ethidium bromide, actinomycin D and papaverin arrested the development of sea urchin embryos at the stage of early gastrula when the synthesis of rRNA increases. The fertilization membrane did not prevent the penetration of hydrocortisone and benzo(a)pyrene in the embryo cells. These drugs did not affect RNA synthesis at the early stages of development and markedly suppressed it at the early gastrula stage. A suggestion is put forward to the effect that the developmental arrest at the early gastrula stage is connected with the suppression of rRNA synthesis. The mechanism of selective sensitivity of rRNA synthesis to a wide range of biologically active substances is discussed.