Anne-Lise Carrie

The cecum does not participate in the stimulation of intestinal calcium absorption by calcitriol.

Intestinal Ca absorption from the diet consumed during one night was measured in male rats fed a normal (0.5%) Ca, low fiber (3% cellulose) diet by determining the decrease in 47Ca/47Sc ratio between diet and feces. One-half of the rats had been cecectomized 9 weeks previously at 14 weeks of age. Calcitriol injections, given intraperitoneally the morning of the experiment, stimulated fractional intestinal Ca absorption 2.5-fold in intact rats (16.9 +/- 2.0% to 42.2 +/- 1.8%) and 2.3-fold in cecectomized rats (20.1 +/- 1.4% to 46.8 +/- 1.2%). Similar results were obtained when the data were calculated in terms of total Ca absorption expressed as mg/day. Thus, although the cecum can absorb Ca when diets contain large amounts of digestible fiber, cecectomy does not influence the stimulation of intestinal Ca absorption induced by calcitriol in vitamin D-replete rats fed a low fiber diet.