Effects of dietary zinc deficiency on hepatic ornithine carbamoyltransferase and alcohol dehydrogenase activities in rats.

Hepatic ornithine carbamoyltransferase (OCT) and alcohol dehydrogenase (ADH) activities were measured in six groups of rats: (A) fed a severe zinc-(Zn-) deficient diet (1.98 ppm) for 5 weeks; (B) pair-fed control for group (A); (C) fed a less severe Zn-deficient diet (6.10 ppm) for 5 weeks; (D) pair-fed control for group (C); (E) fed a Zn-supplemented control diet (90.4 ppm) for 5 weeks; and (F) first fed the severe Zn-deficient diet for 5 weeks and then replaced on the Zn-supplemented control diet until a body weight corresponding to the final weight of group (E) was obtained. Hepatic OCT was similar in all these six groups. On the contrary, hepatic ADH was significantly reduced in groups (A) and (C) and in each of the corresponding pair-fed groups, (B) and (D). No differences were found between groups (A) and (B) or between groups (C) and (D). In group (F), ADH activity improved to a level equivalent to that in group (E). The changes in ADH activities were accompanied by changes in the hepatic Zn content. Thus, it is clear that: (1) the hepatic Zn content may not be affected by the amount of Zn intake alone, but by the combination of Zn and food intake; and (2) ADH, and not OCT, reflected the hepatic Zn content.