Aims: To investigate whether the regulation of aquaporin (AQP) channels is altered by inhibition of type 2 11beta-hydroxysteroid dehydrogenase (11betaHSD2).
Methods: Male Sprague-Dawley rats were treated with glycyrrhizic acid (GA, 2 g/l drinking water) for 7 days. The expression of AQP2 and AQP3 was determined in the kidney by immunoblotting and immunohistochemistry. The expression of Gsalpha and type VI adenylyl cyclase, and the activity of adenylyl cyclase were also determined.
Results: Following the GA treatment, the expression of 11betaHSD2 was significantly decreased in the kidney. The expression of AQP3 was increased, while that of AQP2 remained unchanged. Plasma renin activity and serum aldosterone levels were decreased. Plasma arginine vasopressin (AVP) levels were comparable between the groups. Neither the forskolin-stimulated cAMP generation nor the expression of Gsalpha and type VI adenylyl cyclase was altered significantly.
Conclusion: A decreased expression of 11betaHSD2 may result in an upregulation of AQP3, in which AVP/cAMP-dependent mechanisms are unlikely to be involved.
Copyright 2007 S. Karger AG, Basel.