The effect of the administration of calciferol on the increased calcium excretion induced by thyroxine

Calcium Exchange of the Intestine in Experimental Hyperthyroidism 12

“…Pugsley and Anderson (3,4) and Cope and Donaldson (5) among others confirmed this finding in rats and in human beings, respectively, and in addition, in agreement with Aub (6), stressed the prominent part which loss of calcium in the feces plays in hyperthyroidism, in contrast to other diseases characterized by a negative calcium balance. Hansman and Wilson (7) and Hansman and Fraser (8) recently showed that occasionally calcium equilibrium may be present in clinical hyperthyroidism, and that the intestine need not always be the principal route of excretion of calcium.…”

“…Increased permeability of the intestinal mucosa, active excretion of calcium, and increased absorption of food elements enjoying preferential intestinal absorption were ruled out as factors causing loss of calcium through the feces in hyperthyroidism. 4. From these findings it is concluded that hyperperistalsis and overeating are the chief causes of increased fecal output of calcium in hyperthyroid rats maintained on a calcium-free diet.…”

“…(3) It explains the occasional absence of increased fecal calcium in hyperthyroidism (7,8) by the fact that this is not a primary feature of the disease but depends on the presence of increased intestinal peristalsis and overeating, in themselves secondary manifestations of hyperthyroidism that may occasionally be absent. (4) In conjunction with the mechanism of intestinal absorption discussed above, our theory accounts for the absence of fecal loss of calcium in hyperparathyroidism and other diseases characterized by hypercalcemia and a negative calcium balance but lacking increased intestinal peristalsis and overeating. In these conditions, an abnormally high level of calcium in the blood presumably leads to increased diffusion of calcium into the small intestine, but later this excess of calcium is re-absorbed in the colon with little or no resultant loss of calcium in the feces.…”

Duodenal Calcium Transport in Hyperthyroidism.

“…I t has been known for many years that rats made hyperthyroid with either thyroxine or thyroid extract excrete excessive amounts of fecal calcium ( 1,2). This increase in fecal calcium excretion might be explained by a decrease of calcium absorption or an increase of the movement of calcium into the gastrointestinal tract frolm the animal, or a colmbination of these possibilities.…”