Down-regulation of hepatic and renal 11β-hydroxysteroid dehydrogenase in rats with liver cirrhosis

Abstract

Background & Aims: 11β-Hydroxysteroid dehydrogenase (11β-OHSD) enzymes are responsible for the interconversion of active 11β-hydroxycorticosteroids into inactive 11-ketoglucocorticosteroids and by that mechanism regulate the intracellular access of the steroids to the cognate receptor. A down-regulation of the shuttle of active to inactive glucocorticoids enhances access of glucocorticosteroids to both the glucocorticoid and the mineralocorticoid receptors. In liver cirrhosis, enhanced mineralocorticoid and glucocorticoid effects are observed. We therefore investigated the impact of liver cirrhosis after bile duct ligation on the transcription and activity of 11β-OHSD1 and 11β-OHSD2 in the corresponding tissues. Methods: Messenger RNA from 11β-OHSD1 and 11β-OHSD2 was assessed by reverse-transcription polymerase chain reaction; activity was assessed by measuring the interconversion of corticosterone to dehydrocorticosterone. The effect of bile and bile salts was determined using COS-1 cells transfected with 11β-OHSD1 or 11β-OHSD2. Results: In liver tissue, the messenger RNA ratios of 11β-OHSD1 to glyceraldehyde-3-phosphate dehydrogenase (GAPDH) levels and, in kidney tissue, the ratios of 11β-OHSD2 to GAPDH levels decreased after induction of liver cirrhosis. The 11β-OHSD activities were correspondingly reduced. Bile and individual bile salts inhibited 11β-OHSD1 and 11β-OHSD2 oxidative activity in transfected COS-1 cells. Conclusions: These findings indicate that in liver cirrhosis the mineralocorticoid and glucocorticoid receptor–protecting effects by the 11β-OHSD isoenzymes are down-regulated and that by the same mechanism the glucocorticoid and mineralocorticoid effects are enhanced. GASTROENTEROLOGY 1998;114:175-184