Role of thyroid hormones in the modification of diet-induced thermogenesis by propranolol.

The effect of thyroid hormones on the reduction in resting metabolic rate by the beta-blocker propranolol has been investigated in young pigs. Oxygen consumption was measured 12 to 20 hr after the last meal in euthyroid and hypothyroid animals on a high or low level of energy intake. The increase in resting metabolic rate in animals on the high energy intake was reduced by propranolol in the euthyroid controls but not in those animals made hypothyroid by methimazole. Thus at least part of the action of propranolol to decrease diet-induced thermogenesis depends on its interaction with thyroid hormones.