Protein and Nucleic Acid Metabolism in the Testes of Zinc-deficient Rats

Abstract

The levels and synthesis of protein, RNA, and DNA have been studied in the testes of weanling rats fed zinc-deficient diets during the 2 weeks immediately before attainment of sexual maturity. Control rats were fed zinc-sufficient diets ad libitum or were pair-fed to the deficient rats. Levels of testicular protein, DNA, and RNA were studied at 7 and 14 days after initiation of the zinc-free diets. On day 14 of the experiment, the incorporation of ¹⁴C-leucine into testicular protein and ¹⁴C-adenine into DNA and RNA was also studied. Histological differences were evident in the testes of the zinc-deficient rats on day 14. The zinc content of the testes of rats fed the zinc-deficient diet was always lower than that of the control groups. No gross impairment of DNA synthesis in the testes was noted early in zinc deficiency. The total protein and RNA content of the testes was reduced in zinc-deficient rats but the incorporation of ¹⁴C-leucine and ¹⁴C-adenine into protein and RNA, respectively, was unaltered. These data suggest that an increase in protein and RNA catabolism occurs in the zinc-deficient testes rather than a decrease in synthesis.