11 beta-Hydroxysteroid dehydrogenase: fact or fancy?

Previous attempts to explain the diverse behavior of 11 beta-hydroxysteroid dehydrogenase (11-HSD) within and between species have not been successful. We now propose that 11-HSD activity is the resultant of the coordinated interaction of two enzyme types, 11-dehydrogenase and 11-reductase. We have demonstrated their separate existence by physico-chemical and kinetic methods. Based on these findings, two classes of disease in humans that have been recently described can now be characterized as being associated with a deficiency in either 11-dehydrogenase or 11-reductase.