Effects of angiotensin II,thyroxine and estrogen on plasma renin substrate concentration and renin substrate production by the liver.

The effects of angiotensin II, thyroxine and 17 beta estradiol on plasma renin substrate concentration in rats and renin substrate production by perfused rat livers were investigated. The addition of angiotensin II (1-10 microgram) to the perfusion system did not affect the synthesis of renin substrate. After treatment with thyroxine (2.5 mg/kg/day), plasma renin substrate concentration, plasma renin activity, plasma aldosterone concentration and the rate of renin substrate synthesis were all significantly increased. 17 beta estradiol (2 mg) raised both plasma renin substrate concentration and the amount of renin substrate production by the liver. Isoelectric focusing profiles of renin substrate of liver perfusate and of plasma from estrogen-treated rats were different from that of liver perfusate from normal rats. But the profile of renin substrate in plasma was essentially similar to those to liver perfusates both in normal and estrogen-treated rats.