TIME-RELATED CHANGES INDUCED BY ZINC-DEFICIENT DIET IN THE CONCENTRATION OF RAT CHEEK EPITHELIAL MEMBRANE-COATING GRANULES

Weanling male Sprague-Dawley rats were fed a diet containing 0.4 parts /10(6) zinc and controls were fed an identical diet supplemented with 40 parts/10(6) zinc. After 9, 18 and 27 days of zinc deficiency, speci mens were excised from cheek epithelium and processed for transmission electron microscopy to study the concentration of membrane-coating gr anules (MCG). Their concentration was increased in the granular-cell l ayers of the zinc-deficient epithelium and became significantly greate r after 18 and 27 days than 9 days of deficiency. MCGs appeared in the parakeratinized layers of zinc-deficient epithelium and their concent ration became significantly greater after 27 days in comparison with 9 and 18 days of deficiency. Thus the intracellular retention of MCGs w as increased in the granular and parakeratinized layers with the incre ase in time of zinc deficiency.