Human meibomian glands: a histochemical study for androgen metabolic enzymes

Human meibomian glands were treated for the histochemical demonstration of several enzymatic activities. The 3 alpha-hydroxysteroid dehydrogenase (3 alpha-HSD), 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) and 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) appeared intensely reactive in the differentiating excretory cells, and weakly reactive in the basal cells and in the epithelial cells of the proximal portion of the ducts. The results indicate that meibomian glands can metabolize androgens by the reductive pathway, characteristic of target tissues. The finding of an intense reactivity for the enzymes glucose-6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6PGD) is also discussed.