Impact of Dietary Na+ on Glycyrrhetinic Acid-Like Factors (Kidney 11beta-(HSD2)-GALFs) in Human Essential Hypertension

Abstract

Our previous studies have shown that human urine contains glycyrrhetinic acid-like factors (GALFS) that possess inhibitory activity against kidney 11beta-hydroxysteroid dehydrogenase isoform 2 (HSD2). The present studies were undertaken to determine the impact of dietary Na+ intake on the levels of kidney 11beta(HSD2)-GALFs. The excretion of kidney 11beta(HSD2)-GALFs in 24-hour urine samples of 30 unmedicated subjects (10 normotensive and 10 high/normal-renin and 10 low-renin essential hypertensive subjects) on both 200- and 10-mmol Na (+) diets was studied. No differences in the urinary levels of kidney 11beta(HSD2)-GALFs were observed among the three groups on the high-Na (+) diet. However, with a low-Na+ diet, the levels of kidney 11beta(HSD2)-GALFs were significantly increased in hypertensive subjects but not in normal subjects. Levels increased from 8.3 +/- 1.4 to 17.3 +/- 2.9 and 6.7 +/- 1.3 to 10.6 +/- 1.4 carbenoxolone sodium units/d in high/normal-renin (P =.01) and low-renin hypertensive subjects (P =.07), respectively; normal subjects changed from 8.0 +/- 1.9 to 10.6 +/- 2.4. The levels of kidney 11beta(HSD2)-GALFs were significantly higher in the high/normal-renin hypertensive subjects than in either the control normotensive subjects or the low-renin hypertensive subjects when challenged with the low-Na+ diet (P