Effect of vitamin A deficiency on the testis-specific histone TH2B of the rat

The effect of vitamin A deficiency on rat testis was studied biochemically and histologically. The earliest change in nuclear basic proteins was a decrease and disappearance of the testis-specific protein (TP); the disappearance approximately coincided with cessation of growth. At later stages of deficiency, the testis-specific histone TH2B was markedly reduced and in some cases disappeared, as did the TH1 histone band. Histological studies indicated that the loss of TH2B and TH1 requires a substantial degree of testicular degeneration, because they could still be detected to some extent in testes containing mainly Sertoli cells, reduced numbers of spermatogonia and very few spermatocytes. The effect of retinol in maintaining the germ cells and the testis-specific basic proteins TP and TH2B was very specific, in that it could not be replaced by retinoic acid, which can maintain normal body growth. Prolonged supplementation of vitamin A-deficient animals with retinyl palmitate partially restored the levels of TP, TH2B, and TH1.