Ontogeny of 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase (3 beta-HSD) in human adrenal gland performed by immunocytochemistry.

Human foetal adrenal plays a major role in the synthesis and secretion of steroids which are essential to several physiological events during foetal development. Since 3 beta-hydroxysteroid dehydrogenase 5-ene-4-ene isomerase (3 beta-HSD) is involved in the biosynthesis of all classes of hormonal steroids, namely progesterone, glucocorticoids, mineralocorticoids, androgens and estrogens, knowledge of the ontogeny of 3 beta-HSD should lead to a better understanding of steroidogenesis in the foetal adrenal. Polyclonal antibodies raised against purified human placental 3 beta-HSD were used to localize the enzyme in 22-week, 28-week, and term foetal adrenals as well as in the adrenals of 2-month-, 8-month- and 2-year-old infants. 3 beta-HSD has been identified in the outer cortex, neocortex and zona glomerulosa zone of foetal adrenal, respectively. In 2-month- and 8-month-old infant adrenals, the enzyme was localized in the zona glomerulosa and zone fasciculata while in 2-year-old infants, the immunoreaction was observed also in the zona reticularis, the medulla being devoid of any reaction.