Calcium uptake by isolated rat intestinal cells

Intestinal cells were isolated by a combination of mechanical and enzymatic means, and their calcium uptake was assayed by a rapid filtration procedure. Calcium uptake was a time- and concentration-dependent process that was markedly elevated at 25 and 37 degrees C, as compared to 0 degree C. Cells isolated from rat duodenum exhibited higher uptakes than cells from jejunum, which in turn took up more calcium than cells from the ileum. Duodenal cells from vitamin D-deficient animals took up less calcium than cells from vitamin D-replete cells. In vivo vitamin D repletion with 1,25-dihydroxyvitamin D3 raised calcium uptake by duodenal cells from treated animals toward that of cells from replete rats. Furthermore, calcium uptake by duodenal cells from vitamin D-deficient animals approximated that of ileal cells from replete rats. These findings with isolated cells parallel prior findings of tissue calcium transport and suggest that cellular calcium uptake may be related to the saturable component of intestinal calcium absorption. Isolated intestinal cells may therefore constitute one experimental model for the study of transcellular calcium transport.