ZINC-DEFICIENCY IN ADULT-RATS REDUCES THE RELATIVE ABUNDANCE OF TESTIS-SPECIFIC ANGIOTENSIN-CONVERTING ENZYME MESSENGER-RNA

Zinc deficiency results in reduced testicular angiotensin-converting e nzyme (ACE) activity and reduced amounts of ACE protein in the testes of young rats, In the present study, we examined the effect of zinc de ficiency on the relative abundance of testicular ACE mRNA and its rela tionship to ACE activity over time. Forty-five male rats at 7 wk of ag e were placed on one of three feeding regimens: 1) a diet adequate in zinc, 2) a diet deficient in zinc and 3) a diet adequate in zinc that was fed in an amount equal to that consumed by a paired mate fed the z inc-deficient diet. Rats were killed after 3, 5 and 7 wk. Rats fed the zinc-deficient diet had significantly lower (P < 0.01) body weight ga in and testis weight al each week sampled than the other groups, They also showed compromised zinc status as evidenced by significantly lowe r (P < 0.01) serum and testis zinc concentrations. At each period, rat s fed the zinc-deficient diet had significantly lower (P ( 0.01) testi cular, ACE activity than rats fed either of the zinc-adequate diets. C oinciding with low ACE activity, there was a lower (P < 0.01) relative abundance of ACE mRNA in the group for the zinc-deficient diet than i n either of the zinc-adequate groups. The results suggest that much of the low ACE activity in the testis of rats in the latter stages of zi nc deficiency is attributable to a reduction in ACE gene transcription . However, an effect of the deficiency on ACE mRNA turnover is not rul ed out.