No evidence of a relation between 11beta-hydroxysteroid dehydrogenase type 2 activity and salt sensitivity

The ratio of urinary concentrations of tetrahydrocortisol plus allotetrahydrocortisol to tetrahydrocortisone [(THF + ATHF)/THE] reflects the activity of the enzyme 11beta-hydroxysteroid dehydrogenase type 2 (11BHSD2), which converts cortisol to cortisone in the kidney and thereby protects the mineralocorticoid receptor from the mineralocorticoid action of cortisol. The aim of the present study was to investigate whether 11BHSD2 activity is affected by salt intake and if it is related to salt sensitivity.

Concentrations of THF, ATHF, and THE in 24-h urine collections was determined by gas chromatography at baseline, after 1 week on a low salt diet (10 mmol/d), and after another week on a high salt diet (240 mmol/d) in 29 healthy subjects with heredity for hypertension. Salt sensitivity was defined as the difference between mean arterial blood pressure (BP) after the high salt diet and mean arterial BP after the low salt diet.

The high salt diet increased (THF + ATHF)/THE by 5.1% +/- 9.4% (P =.009) when compared to the low salt diet. The salt-induced change of (THF + ATHF)/THE was not related to salt sensitivity. There was no correlation between salt sensitivity and (THF + ATHF)/THE at baseline (r = -0.18, P =.34), whereas salt sensitivity was inversely related to (THF + ATHF)/THE after the low (r = -0.38, P =.05) and after the high (r = -0.39, P =.04) salt diets.

We found no support for an association between enhanced salt sensitivity and reduced 11BHSD2 activity.