Background: Aging in humans is characterised by a selective decline in circulating levels of adrenal androgens, whose production in Zona Reticularis (ZR) of adrenal is enhanced by Cytochrome-B5 (CytB5). Objectives: The present work aims to determine the histomorphological effects of aging and CytB5 distribution in the adult human adrenal cortex during the aging process. Methods: This is an analytical study in which human adult adrenal glands were obtained at autopsy from 39 men and 33 women who suffered a sudden death. The right & the left adrenal glands were received separately and Gross findings, microscopic features and Immunohistochemistry with CytB5 were studied in detail. Results: The mean of weight, length & breadth of both Right & Left adrenal glands were found to decrease with increasing age, which is statistically significant, but without significant difference in the thickness of adrenal glands. The thickness of ZR and expression of CytB5 also showed statistically significant reduction with increasing age. The area which was histologically identified as ZR on H & E staining, corresponded well to the area of CytB5 positivity on IHC.

Keywords: Cytochrome B5; Adrenal; Aging.