RESULTS	Studies on control subjects after placebo showed that natriuresis occurred during the 6 h after commencement of the saline infusion , with falls in plasma albumin concentration , plasma renin activity and plasma aldosterone concentration ; in comparison with results of mock infusion ( 6 mmol Na + ) there was no change in the urinary excretion of dopamine and noradrenaline ( In their free or conjugated forms ) .\