[Regularity of biochemical differentiation in ontogenesis]

Here we review original data on biochemical differentiation mechanisms. The patterns of the preprogrammed metabolism of the embryo are studied by comparing biochemical mechanisms in undifferentiated embryonic tissues in the course of differentiation and during the terminal establishment of a specialized tissue. This review is composed of three main sections corresponding to the specificity of biochemical differentiation. The first section covers the material on time-related isozyme pattern during skeletal muscle differentiation in a loach (a teleostean fish). The second section presents the data on "incorporated activation", i.e., the appearance of a functional relationship between contractile proteins biosynthesis and the systems of glycogenolysis and glycogen synthesis during the development of chick embryo muscle. The third section covers the data on liver differentiation, the formation of the glycogen organelle with embedded enzymes of glycogen synthesis, and degradation during the development of chick and rat embryos.