[Propranolol effect on renin-angiotensin system kinetics during experimental hyperthyroidism (author's transl)].

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.