Factors controlling adrenal weight and corticosterone secretion in male rats as revealed by median eminence lesions and pharmacological alteration of prolactin secretion.

To determine whether or not prolactin, as well as ACTH, was involved in the control of adrenal weight and steroid release, lesions in the median eminence which had previously resulted in impaired steroid release and atrophy of the adrenal were placed in animals in which the plasma prolactin was allowed to rise as a result of the lesions or prevented from rising by the administration of the dopamine agonist, CB-154. As previously reported, as the severity of diabetes insipidus (DI) increased as a result of interruption of the supraoptico-hypophyseal tract, adrenal weight declined reaching a nadir at water intakes of approximately 100-150 ml/day. This was followed by a reversal of this trend and an increase in adrenal weight as water intakes increased further. These effects were not modified by CB-154 which was effective to lower the elevated prolactin levels in the animals. In general, adrenal weight correlated with levels of plasma corticosterone and progesterone. The ability of the animals to undergo compensatory adrenal hypertrophy was also impaired by median eminence lesions in the presence or absence of CB-154. Exceptional animals were encountered in which adrenal weight was high and yet plasma corticosterone was low. Treatment of hypophysectomized animals with long-acting ACTH plus maintenance doses of triiodothyronine prevented the adrenal atrophy characteristic of the hypophysectomized animal, thus confirming that ACTH is the most important hormone in the control of adrenal weight.(ABSTRACT TRUNCATED AT 250 WORDS)