CALCIUM EXCHANGE OF THE INTESTINE IN EXPERIMENTAL HYPERTHYROIDISM 12

Abstract

Intestinal absorption of Ca lactate administered by stomach tube was unchanged in fasting and in fed hyperthyroid rats. Excretion of Ca into the intestine was also normal in hyperthyroid rats. Adm. of thyroxin or of laxatives in subpurgative doses doubled the fecal excretion of Ca in rats maintained on a Ca free diet. Adm. of morphine to slow peristalsis or restriction of the increased food intake markedly decreased the fecal output of Ca in hyperthyroid rats. Hyperperistalsis and overeating were evidently the chief causes of increased fecal output of Ca in hyperthyroid rats. Decreased intestinal absorption of Ca, increased permeability of the intestinal mucosa and active excretion of Ca were considered ruled out as factors causing loss of Ca in hyperthyroidism.