INFLUENCE OF THE THYROID GLAND ON ABSORPTION IN THE DIGESTIVE TRACT

Publisher Website
Google Scholar
Abstract
Administration of thyroid hormone to rats markedly in- creased the absorption of dextrose, galactose, xylose and oleic acid in the digestive tract, but did not affect the absorption of alanin. Thyroidectomy caused a considerable reduction of the absorption of dextrose in the gastrointestinal tract. Absorption of xylose in the digestive tracts of rats treated with thyroxin is increased apparently through abnormally rapid emptying of the stomach. Absorption of dextrose, galactose and oleic acid in the alimentary tracts of rats treated with thyroxin is increased probably due to stimulation of phosphorylation. The following conditions were ruled out as factors accelerating the absorption of dextrose in hyperthyroid rats: depletion of carbohydrate, increase in basal metabolism, a rise in the velocity of the blood flow, intestinal hyperperistalsis, shortened emptying time of the stomach, and increased permeability of the mucosa. Increased absorption of dextrose in the digestive tract appears to take place chiefly in the intestine. The thyroid hormone apparently influences absorption mainly by increasing phosphorylation, and by stimulating gastric emptying. The discovery that thyroxin specifically stimulates the absorption of substances susceptible of phosphorylation and that phlorizin inhibits this stimulating action, confirms Verzar''s theory of selective intestinal absorption through phosphorylation. Clinically, altered absorption is an important factor in producing abnormally high sugar tolerance curves in patients with hyperthyroidism, and unusually low sugar tolerance curves in patients with myxedema.