Influence of the Thyroid Gland on the Accumulation of Sugars in Rat Intestinal Mucosa during Absorption

Abstract

ACCORDING to Althausen and Stockholm¹ the thyroid gland exerts a marked influence on the absorption of sugars by the small intestine of the rat. Measuring the absorption of orally administered sugars in vivo they showed that thyroidectomized male rats absorbed glucose at about 60 per cent of the rate for normal animals. The treatment of normal animals with thyroid extract had the effect of doubling the rate of glucose absorption. In the case of galactose it was found that in male rats the previous administration of thyroid extract increased the absorption rate to about 150 per cent of that found in normal animals. Many differing factors, all of which are difficult to control, are liable to influence the findings in absorption investigations on animals in vivo^1,2. Intestinal absorption can now be investigated in the isolated intestine in vitro; moreover, the processes underlying sugar transport in the mammalian small intestine are now known to be associated with the accumulation of sugar in the mucosal tissue and, in particular, in the epithelial cells^3–5. We have accordingly examined the effects of the thyroid gland on the capacity of rat intestinal mucosa to accumulate sugars during absorption in vitro.