Nongenomic actions of bile acids. Synthesis and preliminary characterization of 23-and 6,23-alkyl-substituted bile acid derivatives as selective modulators for the g-protein coupled receptor TGR5

23-Alkyl-substituted and 6,23-alkyl-disubstituted derivatives of chenodeoxvcholic acid are identified as potent and selective agonists of TGR5, a G-protein coupled receptor for bile acids (BAs). In particular. we show that methylation at the C-23(S) position of natural BAs confers a marked selectivity for TGR5 over FXR, while the 6 alpha-alkyl substitution increases the potency at both receptors. The present results allow for the first time a pharmacological differentiation of genomic versus nongenornic effects mediated by BA derivatives.