Propranolol effect on renin-angiotensin system kinetics during experimental hyperthyroidism

Abstract

The basal levels of angiotensin I (A.I), plasma renin activity (PRA), plasma renin substrate (PRS) and plasma renin concentration (PRC) were estimated in hyperthyroid rats before and after propranolol treatment.Serum levels of triiodothyronine (T3), thyroxine (T4), angiotensin I both basal and generated by incubation of plasma samples were measured by radioimmunoassay, while, PRC and PRS were evaluated by triiodothyronine or thyroxine treatment induced a decrease in PRS and an increase in PRC whereas triiodothyronine alone produced an increase in the basal levels of angiotensin I and PRA.The propranolol in euthyroid animals not only decreased the basal levels of angiotensin I and PRA, but also prevented the PRC increase in hyperthyroid rats, while restoring at the same time the basal levels of angiotensin I and PRA.