Vitamin D3 and calcium absorption in the chick

Abstract

An attempt has been made to locate the site of action of vitamin D3 as it affects the trans-location of calcium across the intestine. Calcium appears to be pumped out of cells by a process dependent on energy from metabolism. The effects of cold, inhibitors and vitamin D3 on the translocation of calcium by everted sacs of intestine were studied and compared with results obtained in vivo. A model was proposed to explain the results which suggests that vitamin D3 inhibits a metabolically operated pump that returns calcium from the mucosal cell to the lumen. Some observations on the effect of sodium lauryl sulphate on the translocation of calcium in vivo and in vitro are reported.