CHANGES IN THE RENIN-ANGIOTENSIN-ALDOSTERONE SYSTEM IN 2-KIDNEY-2-CLIP GOLDBLATT HYPERTENSIVE RATS OF BOTH SEXES SUBMITTED TO CHRONIC HYPOBARIC HYPOXIA

The effect of chronic hypobaric hypoxia (CHH) on the development of 2k -2c Goldblatt renovascular hypertension has been analyzed in rats of b oth sexes. Results have shown lower values of blood pressure (BP) in a ll the animals exposed to CHH compared with their normoxic control (P< 0.001). Haematocrit was increased by adaptation to CHH (P< 0.001), an d was larger in male than in female hypoxic rats, both normotensive (P < 0.05) and hypertensive (P < 0.01). Plasma renin activity was higher in normoxic and hypoxic hypertensive female rats than in their normot ensive controls (P < 0.05). Plasma angiotensinogen concentration was h igher in normoxic control male rats than in all the other groups. This difference disappeared after adaptation to CHH or development of hype rtension. Plasma aldosterone concentration was lowest in normoxic cont rol male rats and the difference also disappeared after CHH or renal i schemia. Present data indicate that CHH blunts the hypertensive respon se to bilateral renal ischemia in male and female rats. Sexual differe nces related to the mechanisms that could be involved in hypertension development have been observed. The renin-angiotensin-aldosterone syst em might be modulated by gonadal hormones during the development of hy pertension.