11ß-hydroxysteroïddehydrogenase: eigenschappen en klinische betekenis van een sleutelenzym in het cortisolmetabolisme

- The enzyme 11βHSD catalyzes the interconversion of the biologically active cortisol and the biologically inactive cortisone.

- There are two distinct isozymes: 11βHSD type 1 is mainly expressed in liver and is a bidirectional enzyme, with both dehydrogenase and reductase activity. 11βHSD type 2 is mainly expressed in kidney and is a unidirectional enzyme with only dehydrogenase activity.

- 11βHSD type 2 protects the mineralocorticoid receptor from being activated by cortisol. Thus, specificity of this receptor in vivo is enzyme and not receptor mediated.

- The syndrome of apparent mineralocorticoid excess is caused by a congenital deficiency of 11βHSD type 2.

- Liquorice-induced hypertension is an example of an acquired defect in dehydrogenase activity of 11βHSD, caused by glycyrrhetinic acid.

- 11βHSD may play a role in the pathogenesis of ‘essential’ hypertension, obesity and type 1 diabetes mellitus. Angiotensine-converting enzyme inhibitors enhance dehydrogenase activity of 11βHSD, which may contribute to their natriuretic effect.