THERMAL EFFECT OF FOOD IN HYPOTHYROID RATS

The regulatory and obligatory components of cephalic and gastrointesti nal phases of the thermic effect of food (TEF) were measured in contro l and hypothyroid rats. A significant decrease (P<0.05) in regulatory and obligatory components of cephalic and gastrointestinal TEF, after either a control or energy-dense meal, was found in hypothyroid rats c ompared with control rats. Our findings indicate that hypothyroidism i s associated with a decreased thermogenic response to food which contr ibutes to the reduced energy expenditure of hypothyroid rats. Our resu lts also suggest that tri-iodothyronine is involved in the regulation of postprandial thermogenesis directly as well as through its influenc e on beta-adrenergic response and insulin release.