Effects of dietary zinc deprivation on zinc concentration and ratio of apo/holo-activities of angiotensin converting enzyme in serum of mice

Objective

The aim of the present study was to evaluate the effects of dietary zinc deprivation on zinc concentration, the activity of angiotensin converting enzyme (ACE) and ratio of apo/holo-activities of ACE (ACE ratio) in the serum of mice.

Methods

Twenty-two male mice were deprived of dietary zinc for up to 9 days. Zinc concentration in the serum was measured by means of atomic absorption spectrometry. Also, the activity of ACE in the serum was measured by HPLC as the activity of holo-ACE. After addition of zinc to the serum in vitro, the increase of ACE activity over the initial value was determined as that of apo-ACE. Finally, the ratio of apo/holo-ACE activities was calculated.

Results

There was a significant decrease of zinc concentration, but a slight decrease of the activity of ACE in the serum of mice by intake of zinc-deficient diet for 9 days. ACE ratio tended to increase on day 5 and was significantly increased on day 9 in mice deprived of dietary zinc.

Conclusion

These findings suggest that ACE ratio is as sensitive as serum zinc concentration for the evaluation of zinc deficiency and can be used for the biochemical diagnosis of zinc nutritional status in patients with zinc deficiency-induced taste impairment.