INDEPENDENCE OF THE THYROID AND ADRENAL GLAND IN POTASSIUM THIOCYANATE (KCNS) INDUCED HYPOTENSION IN RATS

Abstract

ABSTRACT KCNS administered to intact rats depressed thyroidal radioiodine (131I) uptake and accelerated thyroidal 131I release. A marked thyroidal hypertrophy was present following administration of KCNS for 16 days. The same treatment caused a sustained fall in blood pressure (BP). This hypotensive effect was not affected by thyroxine treatment, thyroidectomy, thyroidectomy plus thyroxine treatment, placement of a hypothalamic lesion, and hypophysectomy plus thyrotrophin (TSH) treatment. Pituitary-adrenal activity in KCNS-treated rats was not changed but the secretion of aldosterone appeared to be increased. A lowering of BP following KCNS treatment also occurred in adrenalectomized rats, and in adrenalectomized rats treated with corticosterone or aldosterone. Dexamethasone in adrenalectomized as well as in intact rats blocked KCNS-induced hypotension. From this study it is concluded that the lowering of BP as caused by KCNS treatment in the rat, is independent of alterations in the function of the thyroid and the adrenal gland.