Pancreatic beta-cell K(ATP) channel activity and membrane-binding studies with nateglinide: A comparison with sulfonylureas and repaglinide.
Nateglinide (A-4166) is an amino acid derivative with insulinotrophic action in clinical development for treatment of type 2 diabetes. The aim of this study was to determine whether nateglinide's interaction at the K(ATP) channel/sulfonylurea receptor underlies its more rapid onset and shorter duration of action in animal models. Binding studies were carried out with membranes prepared from RIN-m5F cells and HEK-293 cells expressing recombinant human sulfonylurea receptor 1 (SUR1). The relative order for displacement of [(3)H]glibenclamide in competitive binding experiments with RIN-m5F cell membranes was glibenclamide > glimepiride > repaglinide > glipizide > nateglinide > L-nateglinide > tolbutamide. The results with HEK-293/recombinant human SUR1 cells were similar with the exception that glipizide was more potent than repaglinide. Neither nateglinide nor repaglinide had any effect on the dissociation kinetics for [(3)H]glibenclamide, consistent with both compounds competitively binding to the glibenclamide-binding site on SUR1. Finally, the inability to measure [(3)H]nateglinide binding suggests that nateglinide dissociates rapidly from SUR1. Direct interaction of nateglinide with K(ATP) channels in rat pancreatic beta-cells was investigated with the patch-clamp method. The relative potency for inhibition of the K(ATP) channel was repaglinide > glibenclamide > nateglinide. Kinetics of the inhibitory effect on K(ATP) current showed that the onset of inhibition by nateglinide was comparable to glibenclamide but more rapid than that of repaglinide. The time for reversal of channel inhibition by nateglinide was also faster than with glibenclamide and repaglinide. These results suggest that the unique characteristics of nateglinide are largely the result of its interaction at the K(ATP) channel.
Hu
S
S
Metabolic and Cardiovascular Disease Department, Novartis Institute for Biomedical Research, Summit, New Jersey 07901, USA.
Wang
S
S
Fanelli
B
B
Bell
P A
PA
Dunning
B E
BE
Geisse
S
S
Schmitz
R
R
Boettcher
B R
BR
D018528:ATP-Binding Cassette Transporters; D000818:Animals; D001667:Binding, Competitive / Q000187:drug effects; D002219:Carbamates / Q000493:pharmacokinetics / Q000494:pharmacology*; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002469:Cell Separation; D002478:Cells, Cultured; D003510:Cyclohexanes / Q000494:pharmacology*; D005947:Glucose / Q000378:metabolism; D005905:Glyburide / Q000494:pharmacology; D016695:Glycosyltransferases; D006801:Humans; D007003:Hypoglycemia / Q000097:blood / Q000139:chemically induced; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D066298:In Vitro Techniques; D007328:Insulin / Q000378:metabolism; D007515:Islets of Langerhans / Q000378:metabolism*; D054086:KATP Channels; D007700:Kinetics; D008297:Male; D008565:Membrane Proteins; D000077715:Nateglinide; D018408:Patch-Clamp Techniques; D010649:Phenylalanine / Q000031:analogs & derivatives* / Q000494:pharmacology; D010880:Piperidines / Q000493:pharmacokinetics / Q000494:pharmacology*; D026902:Potassium Channel Blockers; D015221:Potassium Channels / Q000187:drug effects*; D024661:Potassium Channels, Inwardly Rectifying; D051381:Rats; D017207:Rats, Sprague-Dawley; D012097:Repressor Proteins / Q000096:biosynthesis / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D013453:Sulfonylurea Compounds / Q000493:pharmacokinetics / Q000494:pharmacology*
D018528:ATP-Binding Cassette Transporters; D002219:Carbamates; D003510:Cyclohexanes; D007004:Hypoglycemic Agents; D007328:Insulin; D054086:KATP Channels; D008565:Membrane Proteins; D010880:Piperidines; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D013453:Sulfonylurea Compounds; C092520:uK-ATP-1 potassium channel; D000077715:Nateglinide; D010649:Phenylalanine; C072379:repaglinide; D016695:Glycosyltransferases; C092031:SUR1 protein, S cerevisiae; D005947:Glucose; D005905:Glyburide