Biochemical evidence of the functional recovery and regeneration of adrenal autotransplants in the rat spleen.

Adrenal transplantation may restore adrenal function after bilateral adrenalectomy or when adrenal function is lost. Thus, animal experiments could provide useful information before clinical application of adrenal transplantation. Using an experimental model of autotransplantion of a complete adrenal gland in the spleen of adrenalectomized rats, several biochemical and hormonal parameters were studied to evaluate the function of transplanted adrenal tissue compared to control and adrenalectomized animals. Three weeks after surgery, the animals were sacrificed and plasma and tissue samples were obtained for biochemical studies. In the autotransplanted rats, plasma glucose, hepatic glycogen, plasma, and hepatic proteins, which were decreased in adrenalectomized rats, increased to values close to those of the control group; whereas muscle and thymus proteins, which were increased in adrenalectomized animals, decreased and reached normal levels. Corticosterone plasma levels in autotransplanted rats showed a 50% recovery compared to control animals, whereas plasma aldosterone concentrations were low, with similar values to those of the adrenalectomized group. These results provide evidence that the adrenal grafts secrete corticosterone in quantities enough to overcome hepatic inactivation. On the other hand, aldosterone plasma concentrations remain very low, plasma potassium levels are increased, and plasma sodium levels are decreased in animals with intrasplenic adrenal grafts, indicating that aldosterone production is insufficient to avoid hypoaldosteronism.