[Effect of vitamin A provision on antineoplastic resistance in rats].

While studying Guerin's carcinoma development under conditions of different vitamin A provision in the period of tumor growth and before it appearance, it was established, that strengthened saturation of an organism with a tumor by vitamin A hyper doses can both stimulate and inhibit tumor progression. The effect depends on duration of vitamin A administration and on the level of preliminary provision of an organism with this vitamin. The hyper doses administration for 7 days on the normal vitamin A provision background and the normal doses administration to vitamin A-deficient animals which is especially expressed antitumor effect. The continuation of hyper doses administration to 14 days leads to rising of tumor sizes, especially expressed in vitamin A-deficient animals.