[Effects of vitamin A on formation of aminoacyl-tRNA].

The melting temperature and hyperchromia of intestine mucosa tRNA preparations and the effect of inactivating factors on aminoacyl-tRNA-synthetase activity were studied at the stage of hypovitaminosis and under deep A-avitaminosis. It is shown that in the aminoacylation reaction, aminoacyl-tRNA-synthetase is a component more sensitive to vitamin A deficiency.

[Effect of vitamin A in significant doses on incorporation of (14C) retinol, acceptor capacity of tRNA and activity of certain enzymes in tissues and plasma membranes of cells in the presence of Guerin's carcinoma].

In rats with Guerin's carcinoma the weight and size of the tumour is twice as low when significant doses of vitamin A are administered. Under these conditions the acceptor capacity of tRNA of the small intestine mucosa as well as the intensity of [14C] retinol incorporation into plasma membranes of its cells decrease essentially, whereas in the mucosa itself the radioactivity remains high. When studying the activity of alkaline phosphatase, amylase in the mucosa and arginase in the liver, a disproportion is found in changes in the enzymes activity on the surface of the small intestine mucosa and in the mucosa homogenate, that may be due to a change in the state of the cell membrane apparatus when the tumour is formed.

[On the potential protective properties of vitamin A in carcinogenesis].

The effect of massive doses of vitamin A was studied as applied to the tumor growth in rats with Guerin's carcinoma, protein biosynthesis in them and enzymic activity. It is established that intraperitoneal administration of vitamin A massive doses (the total quantity being 4000 000 and 2000 000 I.U.

[Serum and tissue aspartate and alanine aminotransferases activity of rats with vitamin A deficiency].

The activity of aspartate-(AST) and alanine (ALT) aminotransferases was studied in the tissues and blood serum of rats under conditions of A-avitaminosis. The activity of aminotransferases is established to increase in the blood serum and liver. In the small intestine mucose it drops sharply.