A COMPARISON OF THE DEVELOPMENT OF RENAL-HYPERTENSION IN MALE AND FEMALE RATS

1. The objective of this study was to determine the influence of gende r on the development of renal hypertension in Sprague-Dawley rats usin g the Goldblatt two-kidney, one-clip (2KIC) model. In addition, this s tudy examined the effect of ovariectomy upon the development of hypert ension in female rats. 2. At 10 weeks of age, male, intact female and ovariectomized female rats underwent clipping of the right renal arter y or sham operation. Tail-cuff plethysmography was used to monitor the systolic blood pressure of all animals for 7 weeks post-clipping or s ham operation. Rats were subgrouped according to whether or not they d eveloped hypertension (systolic blood pressure greater than or equal t o 150 mmHg). 3. Within 2 to 3 weeks of clipping, hypertension was indu ced in only 53% (n = 120) of the intact female 2K IC rats, but in 83% (n = 18) of the male and 78% (n = 18) of the ovariectomized female rat s. 4. Seven weeks after right renal artery clipping, plasma renin acti vity was determined in a subset of each group and was found to be 5-6 fold higher in male (17.29 +/- 4.04 ng angiotensin l . h(-1) . ml(-1)) and ovariectomized female (9.71 +/- 1.25 ng angiotensin l . h(-1) . m l(-1)) hypertensive rats compared with their respective normotensive o r sham-operated counterparts (3.39 +/- 0.58 ng angiotensin l . h(-1) . ml(-1) and 1.60 +/- 0.41 ng angiotensin l . h(-1) . ml(-1) respective ly) (P < 0.05, analysis of variance). In contrast, the plasma renin ac tivity measured in intact female hypertensive rats was not significant ly different from that measured in the corresponding 2KIC normotensive or sham-operated groups. 5. These results indicate that the success r ate of inducing renal hypertension in Sprague-Dawley rats is higher in males than in intact females. Furthermore, these results suggest that the induction of 2KIC hypertension may be influenced by ovarian hormo nes.