GONADAL-HORMONES MODULATE DEOXYCORTICOSTERONE-SALT HYPERTENSION IN MALE AND FEMALE RATS

We have shown previously that, in rats with deoxycorticosterone (DOC)- salt hypertension, arterial blood pressure rises more rapidly and reac hes a higher level in male than in female rats and that the course of the hypertension was ameliorated by gonadectomy in male rats and exace rbated by gonadectomy in female rats. The present investigation was un dertaken to examine the role of the gonadal steroid hormones in modula ting the course of DOG-Salt hypertension in the rat. Our previous find ings with respect to the effects of gender and gonadectomy on DOG-salt hypertension were confirmed in this study. Chronic treatment with gon adal steroids was begun 1 week before the start of the DOG-salt protoc ol. 17 beta-Estradiol attenuated the course of the hypertension in int act male rats and in gonadectomized females. Testosterone exacerbated the development of the hypertension in gonadectomized male rats but wa s without effect in intact females. Progesterone alone had no effect o n the hypertension in ovariectomized rats but when given to ovariectom ized rats in combination with estradiol transiently prevented the amel iorating effect of the estradiol. These effects of the gonadal steroid hormones could not be attributed to effects of saline intake. Thus, t hese findings demonstrate that the gonadal steroid hormones play an im portant role in modulating the pathogenesis of DOC-salt hypertension i n the rat. It is suggested that the effects of the gonadal hormones on the course of the hypertension may be due to modulation of the cardio vascular and renal actions of vasopressin, since vasopressin is requir ed for this model of hypertension.