ZINC-DEFICIENCY REDUCES THE ACTIVITY OF ANGIOTENSIN-CONVERTING ENZYMEIN TESTICULAR GERM-CELLS AND SPERM OF ADULT-RATS

Zinc deficiency reduces the activity of angiotensin-converting enzyme (ACE) in the testes of young rats. However, it was not known whether t his effect was specific to the testicular germ cell that contains most of the ACE activity or whether it was caused by a reduction in the nu mber of germ cells. Also unknown was whether zinc deficiency could red uce ACE activity in testes of adult rats. Thirty young adult (9 weeks old) male rats were divided into three groups and fed different regime ns for 8 to 10 weeks. The regimens consisted of a zinc-adequate diet ( +ZnAL), a zinc-deficient diet (-ZnAL), and a zinc-adequate diet pair-f ed to those receiving the deficient diet (+ZnPF). Sperm and germ cells were separated from the testes and ACE activity was determined. ACE a ctivity in germ cells from the -ZnAL group was only 50% of that from e ither control group. Likewise, ACE activity from testicular sperm was only 25% of that in the control groups. ACE activity was directly prop ortional to the amount of zinc in each cell type. It was concluded tha t zinc deficiency not only affects the activity of testicular ACE in y oung immature rats, but also affects activity in adult rats if the def iciency is continued long enough. This study also clearly shows that t he effect of the deficiency on ACE activity in the testes is at the ce llular level. (C) 1995 Wiley-Liss, Inc.