Lactose and Calcium Transport in Gut Sacs

Abstract

The effects of glucose and lactose upon calcium absorption in rats were investigated using the inverted gut sac technique with Ca⁴⁵. In weanling animals calcium transport was stimulated by lactose both in the duodenum where calcium is absorbed against a concentration gradient and in the lower intestine where absorption is by passive diffusion. The ability of lactose to stimulate transport was lost as the animals became older, and was not clearly demonstrable after the animals were 6 weeks of age. The active transport of calcium against a concentration gradient in the upper intestine is partially dependent upon the amount of calcium in the diet the animals receive. Only a slight and insignificant effect of dietary calcium upon calcium transport in the lower intestine could be shown.