3 beta HSD and CYB5A double positive adrenocortical cells during adrenal development/aging

Androstenedione is a common precursor of sex steroids produced and secreted in the human adrenal gland and produced by 3 beta-hydroxysteroid dehydrogenase (3 beta HSD), 17 beta-hydroxylase/17,20-lyase (CYP17) and cytochrome b5 (CYB5A). 3 beta HSD is expressed in the zona glomerulosa (ZG) and fasciculata (ZF), CYP17 in the ZF and zona reticularis (ZR) and CYB5A in the ZR, respectively. We previously demonstrated the presence of cortical parenchymal cells co-expressing 3 beta HSD and CYB5A with hybrid features of both ZF and ZR in human adrenal cortex and hypothesized that these cells may play an important role in androstenedione production in human adrenal gland. Age-related morphologic development of these hybrid cells has, however, not been studied. Therefore, in this study, 48 human adrenal specimens from various age groups were retrieved. Double-immunohistochemical analyses were used in order to study the correlation between this hybrid cell type and age. In both male and female adrenal cortex, the means of total adrenocortical area, the area positive for CYB5A and its ratio reached highest peak in the 21-40-year-old (y.o.) group. The greatest overlap between 3 beta HSD and CYB5A in both total and relative area was present in the 13-20 y.o. group. For all the markers mentioned above, statistically significant differences were detected among the different age groups examined (p<0.05). These findings indicated that both area and ratio of 3 beta HSD and CYB5A double positive cells, which could represent the hybrid cells of ZF and ZR, are correlated with human adrenal development and could subsequently influence age-related serum androstenedione levels.