Molecular Basis of Human Salt Sensitivity: The Role of the 11β-Hydroxysteroid Dehydrogenase Type 21

Salt-sensitive subjects (SS) increase their blood pressure with increasing salt intake. Because steroid hormones modulate renal sodium retention, we hypothesize that the activity of the 11β-hydroxy-steroid dehydrogenase type 2 (11βHSD2) enzyme is impaired in SS subjects as compared with salt-resistant (SR) subjects. The 11βHSD2 enzyme inactivates 11-hydroxy steroids in the kidney, thus protecting the nonselective mineralocorticoid receptor from occupation by glucocorticoids. We performed an association study using a recently identified single AluI polymorphism in exon 3 and a polymorphic microsatellite marker of the HSD11B2 gene in 149 normotensive white males (37 SS and 112 SR). The activity of the enzyme 11βHSD2 was assessed by determining the urinary ratio of cortisol (THF+5αTHF) to cortisone (THE) metabolites by gas chromatography in all the 37 SS subjects and in 37 age- and body habitus-matched SR volunteers. Mean (THF+5αTHF)/THE ratio was markedly elevated in SS subjects compared with SR subjects (1...