Abstract
The adrenal gland of hypophysectomized Sprague-Dawley rats showed substantial atrophy 9 days after operation. Histologically-detectable changes in lipid distribution were observed in the zonae glomerulosa, fasciculata and reticularis following hypophysectomy, and a redistributuion of lipid in all 3 zones was effected with [alpha]-ACTH. In addition, a synergism between [alpha]-ACTH and pituitary growth hormone (somatotropin) was demonstrated, the magnitude of the effect being conditioned by the level of exogenous [alpha]-ACTH. These results indicate that somatotropin operates synergistically with ACTH when the 2 hormones are administered in combination to the hypophysectomized rat.