Influence of exogenous glucocorticoids and ACTH on experimental adrenal autografts

Minced adrenal autografts under the renal capsule in adrenalectomized rats were studied by means of serial plasma corticosterone determination and histologic examination. The effect of daily treatment with dexamethasone with or without daily porcine adrenocorticotropic hormone (ACTH) gel was determined. Control autografted rats regained normal corticosterone levels by the 2nd week and at 80 days showed full regeneration of adrenal grafts. Dexamethasone treatment completely suppressed corticosterone and resulted in striking atrophy persistent at 80 days. Porcine ACTH plus dexamethasone resulted in full regeneration with cellular hypertrophy exceeding that of controls, but the corticosterone levels in samples drawn just before the scheduled ACTH injections were very low because the effect of ACTH gel lasted only 12 hr and endogenous ACTH was suppressed. Plasma levels at 40 days were 22.8 +/- 5.9 (SD) for controls, 3.8 +/- 6.1 for dexamethasone, and 5.1 +/- 4.8 for dexamethasone plus porcine ACTH. The results indicate that ACTH is necessary for the optimal regeneration of implanted adrenal autografts.