Cardiovascular and renal effects of central administration of a mineralocorticoid receptor antagonist in conscious female rats

In a previous study we showed that in normotensive male rats brain mineralo corticoid receptor blockade induced a long lasting decrease in blood pressu re associated with increased urinary excretion of water and electrolytes. H ere, we report the effect of intracerebroventricular injection of a mineral ocorticoid receptor antagonist (RU28318; 3,3-oxo-7 propyl-17-hydroxy-andros tan-4-en-17yl-propionic acid lactone) on cardiovascular and renal function in female rats. Compared with male rats, females are less sensitive to brai n mineralocorticoid receptor blockade. Administration of RU28318 (10 ng, 10 0 ng) caused a significant decrease in systolic blood pressure (10-12.5%) o nly at 8 h after injection. An increased urinary excretion of water (about 160%) and electrolytes (about 175%) during the first 8 h after the injectio n was observed in the 100 ng RU28318 treated group. Heart rate, food intake and water consumption were not affected at either dose. In conclusion, in conscious female rats, brain mineralocorticoid receptors participate in blo od pressure and renal function control. (C) 1999 Elsevier Science B.V. All rights reserved.