Characteristics of Adrenal-Regeneration and Aldosterone Hypertension

Unilaterally nephrectomized rats were subjected to either unilateral adrenalectomy, bilateral adrenalectomy or unilateral adrenalectomy and contralateral adrenal enucleation and given 1% sodium chloride solution to drink. Their response to the daily administration of 100 μg of d-aldosterone acetate was compared. Hormone-treated or adrenal enucleated rats both developed hypertension at about the same rate and with a comparable incidence and severity, and in this respect the two influences were not additive. In contrast to adrenal enucleation, aldosterone treatment caused impairment of growth and thymus involution. Thymus glands of aldosterone-treated bilaterally adrenalectomized rats were nonetheless larger than those of untreated enucleated rats. Although adrenal enucleation induced saline polydipsia and caused kidney enlargement, both responses were significantly greater in hormone-treated rats. The implication of these findings with respect to the role which endogenous aldosterone hypersecretion has been suspected of playing in the genesis of adrenal-regeneration hypertension is considered.