Studies on the effect of vitamin D on calcium absorption and transport.
1. Mucosal cells of the small intestine obtained from rats deprived of vitamin D or given excessive amounts of the vitamin accumulated significantly more calcium than did cells from control animals. 2. Mucosal cells from vitamin D-deficient rats released less calcium than did cells from normal or hypervitaminotic D animals. 3. Studies in vivo showed that the transfer of (45)Ca from the intestine to the blood was delayed in vitamin D deficiency, but was accelerated in hypervitaminosis D. 4. The findings support the thesis that vitamin D is involved in the release of calcium rather than in its uptake by mucosal cells. 5. Further evidence is presented suggesting that uptake of calcium by intestinal mucosal cells at 0 degrees is primarily passive, whereas at 38 degrees uptake and release are effected by an active process that depends on energy derived from glycolytic activity.
D000818:Animals; D001693:Biological Transport, Active; D002118:Calcium / Q000097:blood / Q000378:metabolism* / Q000494:pharmacology; D002127:Calcium Isotopes; D003470:Culture Media; D004247:DNA / Q000378:metabolism; D006019:Glycolysis; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D007413:Intestinal Mucosa / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D051381:Rats; D013268:Stimulation, Chemical; D013696:Temperature; D013997:Time Factors; D014807:Vitamin D / Q000008:administration & dosage / Q000494:pharmacology; D014808:Vitamin D Deficiency / Q000378:metabolism
D002127:Calcium Isotopes; D003470:Culture Media; D014807:Vitamin D; D004247:DNA; D002118:Calcium