Effect of propranolol on glucose disposal rate in patients with hyperthyroidism

The effect of propranolol treatment (60 mg per day, three days) on glucose disposal rate (K-value) was investigated in nine patients with hyperthyroidism. K-value was improved in 4 cases and aggravated in 5 cases. The fasting levels of plasma free fatty acids (FFA) before the administration of propranolol in the improved cases were significantly higher than those in the aggravated cases. The propranolol treatment markedly reduced FFA levels only in the improved cases. These results suggest that the impaired glucose tolerance frequently seen in hyperthyroidism patients could be partly attributed to the increased level of plasma FFA.