MODULATION OF AUTOTRANSPLANTED ADRENAL-GLAND BY ENDOTHELIN-1 - A MORPHOLOGICAL AND BIOCHEMICAL-STUDY

Background: Adrenal gland autotransplantation, a model of cortical tis sue regeneration, provides the reconstruction of distinct functional a nd morphological zonae. A morphological and biochemical study of the a drenal gland of adult male rats after autotransplantation and endothel in-1 (ET-1) administration was made. Methods: The technique involved b ilateral adrenalectomy and placement of pieces of the adrenal gland in a dorsal plane between the skin and muscle, The animals were killed 9 0 days after the autotransplantation and 1 hr after intravenous ET-1 a dministration (0.5 mu g/kg body weight), The autotransplanted pieces w ere removed, fixed, and processed for light and electron microscopic m orphologic studies, Trunk blood was collected for steroid assay. Resul ts: Saline-treated control autotransplanted animals showed no remarkab le differences in adrenal organization; grafts exhibiting a mass of re generated cortical tissue were arranged in nests of glandular cells su rrounded by a fibrous capsule and intersected by layers of connective tissue, The adrenal medulla was systematically absent, Ultrastructure of ET-1-treated animals revealed an inner area in the graft, consistin g mainly of fasciculatalike cells. Cytoplasmic changes were evident, w ith high variations in mitochondrial size and arrangement, Profiles of smooth endoplasmic reticulum sometimes exhibited evidence of hypertro phy. Glandular cells in the graft outer area (subcapsular) were almost invariably like glomerulosa; however, some of them showed mitochondri a with a peculiar arrangement of the cristae, ''Hybrid'' cells with mi tochondria resembling those of the zona reticularis were also observed in the subcapsular environment, ET-1-stimulated animals showed signif icant increases in plasma corticosterone and aldosterone concentration s. Conclusions: Endothelin-1, previously reported to stimulate acutely the aldosterone secretion by the adrenal zona glomerulosa in the rat, seems to exert a modulator role on the physiology of adrenal autotran splants, their regeneration and secretion. (C) 1996 Wiley-Liss, Inc.