Bile secretion during experimental hyperthyroidism in the dog

Abstract

Experimental hyperthyroidism in the dog was accompanied by a significant decrease in the enterohepatic content of bile acids with no significant change in biliary cholesterol output. Plasma cholesterol concentrations decreased consistently in all hyperthyroid dogs. Alterations in the diet were followed by marked changes in bile secretion both in the euthyroid and hyperthyroid dogs. The euthyroid dogs given a diet supplemented with protein and cholesterol secreted greater amounts of cholesterol and bile acids into bile. Hyperthyroidism, induced in dogs given the supplemented diet, was associated with a decrease in the biliary output of both cholesterol and bile acids when compared with the controls given the supplemented unchanged. Changes in the secretion of biliary steroids and sterols during experimental hyperthyroidism in the dog may be the result of a disproportionate increase in the rate of the oxidation of acetate. Confirming earlier investigations in thyroidectomized dogs, dietary constituents may influence plasma cholesterol concentrations in the dog regardless of the state of thyroid activity.