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Homeostatic regulation of zinc absorption in the rat

Evans, G.W., Grace, C.I., Hahn, C.
Proceedings of the Society for Experimental Biology and Medicine 1973 v.143 no.3 pp. 723-725
zinc, intestinal absorption, nutrition physiology, homeostasis, nutrient balance, animal nutrition, nutrient deficiencies, blood chemistry, rats
For 7 or 13 days Sprague-Dawley rats 70 to 90 days old were given a stock diet, a diet which contained less than 1 mu g Zn/g without or with 200 mu g Zn as ZnCl2 24 h before Zn absorption was estimated, or the same diet but with 50 mu g Zn/ml added to the drinking water. 65Zn 1 mu Ci was given by tube into the stomach 1 h before all were killed. As Zn deficiency progressed Zn concentration of the intestinal mucosa decreased whereas both the amount of 65Zn taken up by the mucosa and the absorption of 65Zn increased. Zn in plasma was 115 mu g/100 ml for those given adequate Zn, and was 60 and 54 mu g/100 ml, respectively, for those deprived of Zn for 7 and 13 days. When rats deprived of Zn were given ZnCl2, Zn in plasma and intestine rose and there was a fall in 65Zn uptake by the intestine and in absorption of 65Zn. It is suggested that Zn absorption is regulated, in part, by the Zn content of the intestinal mucosa which, in turn, is regulated by the Zn content of the plasma.r.