Effect of Time of Reduction of Renal Mass on Development of Adrenal-Regeneration Hypertension. ∗

Abstract

Summary

1. Salt-treated, uninephrecto-mized-adrenalectomized and contralaterally adrenal enucleated female rats in which those operative steps are performed shortly after weaning (zero time) show a higher mean terminal blood pressure and greater enlargement of heart, kidney, brain and spleen than do similar rats that are operated on 2 weeks after zero time. 2. Performance of the uni-nephrectomy 2 weeks after uniadrenalectomy and adrenal enucleation results in significantly lower terminal mean blood pressure and correspondingly lower lesion severity indices. This suggests that the enucleation step proper is the crucial operation in bringing about the full severity of the hypertensive syndrome. 3. Uninephrectomy and uniadrenalectomy on day zero and contralateral enucleation of the compensatorily-hypertrophied adrenal 2 weeks later results in mean terminal blood pressure and lesion severity indices comparable to those rats in which these operations are carried out at zero time. Blood pressure only rises steeply after the hyper-trophied adrenal gland is enucleated. 4. It is concluded that, while reduction of renal mass contributes greatly to the development of this form of experimental hypertension, enucleation of the adrenal is the decisive step. It is further concluded that this combination of operations early in infancy finds a more favorable internal environment for the development of severe hypertensive cardiovascular disease.