The effect of beta-adrenergic blockade on metabolic rate and peripheral thyroid metabolism in obesity.

The interactions of catecholamine and thyroid hormones in determining changes in metabolic rate were assessed in obese patients given propranolol, both on weight maintenance diet and during semistarvation. Propranolol reduced the resting metabolic rate by 8.6% on a weight maintenance diet but had no effect during energy restriction. Since propranolol led to a similar fall in triiodothyronine (T3) and an increase in reverse T3 on both diets, the early fall in RMR on semi-starvation may depend on catecholamine-mediated mechanisms. Beta-adrenergic blockade might promote energy retention on a normal energy intake but should not reduce the efficacy of slimming diets.