[Effect of alpha- and beta-adrenoreceptor blockaders on thyroid function in rats of various ages]

The effect of alpha-adrenoblocker dibenamine and beta-adrenoblocker propranolol on the blood level of thyroid hormones (TH) and TH production by isolated thyroids (T) was investigated in adult and old male rats. Isolated T were incubated for 4 h in medium 199 with or without TSH (100 mU/ml). TH blood concentration and specific TH production by isolated T was decreased with age. TSH stimulated thyroid hormone production in isolated T only in adult rats. Alpha- or beta-adrenoblockers administration resulted in a decrease in the TH blood concentration, basal and TSH-stimulated thyroid hormone production in adult rats. The results obtained suggested that aging was accompanied by decreased adrenergic control of thyroid function.