Restoration of adrenal-regeneration hypertension in corticosterone-blocked rats by ACTH.

Abstract

Adrenal-regeneration hypertension developed uniformly in uninephroadrenalectomized, contralaterally adrenal-enucleated rats, but not in uninephroadrenalectomized controls, maintained on a high salt intake. Adrenal regeneration and the accompanying hypertension were both blocked by daily administration of 1 mg of corticosterone. One unit of ACTH gel given daily had no effect on either the blood pressure or the adrenal weight of rats with uncomplicated adrenal-regeneration hypertension or those in which blood pressure elevation was blocked with corticosterone. There were no significant differences in thymus weight between any of the foregoing groups. The daily administration of 4 units of ACTH permitted only slight enlargement of the adrenals of corticosterone-blocked, adrenal-enucleated rats, or of the hypertrophying adrenals of unilaterally adrenalectomized rats. Hypertension was fully restored to the former, but was not developed in the latter. Both groups displayed a degree of thymus involution. It would appear that full morphologic regeneration is not a prerequisite of adrenal-regeneration hypertension, but that adequate steroidogenesis to support the change can be elicited from an atrophied adrenal gland by adequate ACTH stimulation. The thymolytic effect of ACTH is analyzed for its possible relevance in respect to the secretory profile of adrenosteroids.