ABSTRACT
BACKGROUND: A substantial body of evidence indicates that reduced plasma adiponectin levels may be key in the development of insulin resistance, type 2 diabetes and the metabolic syndrome. Glucocorticoids decrease the levels of adiponectin in animals and humans. Cortisone is transformed to its active form cortisol, via 11beta-hydroxysteroid dehydrogenase (HSD) type 1. This study sought to ascertain if inhibition of 11beta HSD1 with a new selective inhibitor, BVT116429, affects the concentrations of circulating adiponectin with concomitant effects on glucose homeostasis in diabetic mice. RESULTS: KKAy mice were treated with BVT116429 (3, 10, 30 mg/kg), rosiglitazone (5 mg/kg) or vehicle once daily for ten days. Plasma adiponectin levels rose in mice treated with BVT116429 and this was found to be both the hexameric and the high molecular weight multimeric forms of adiponectin. Seven days of treatment with the 11beta HSD1-inhibitor BVT116429 decreased basal insulin levels but no changes in glucose tolerance were seen. After ten days of treatment, fasting blood glucose level was decreased by BVT116429 comparable to the effects of rosiglitazone. Another 11beta HSD1 inhibitor, BVT2733, improved HbA1c but had no effect on adiponectin. CONCLUSION: Inhibition of 11beta HSD1 can be expected to be beneficial for treating the pathology of type 2 diabetes mellitus. The differences seen in adiponectin between BVT116429 and BVT2733 could be explained by different pharmacodynamics exerted by the compounds in different tissues in the body. Increases in adiponectin concentrations may be an integral component in the mechanism of action of this new11beta HSD1 inhibitor and may be a useful marker of efficacy during the clinical development of 11beta HSD1 inhibitor compounds.
Subject(s)
11-beta-Hydroxysteroid Dehydrogenase Type 1/antagonists & inhibitors , Adiponectin/blood , Blood Glucose/metabolism , Diabetes Mellitus, Experimental/blood , Enzyme Inhibitors/pharmacology , Homeostasis/drug effects , Phenethylamines/pharmacology , Thiazoles/pharmacology , Animals , Diabetes Mellitus, Experimental/enzymology , Insulin Resistance , Male , Mice , Mice, Mutant StrainsABSTRACT
The peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors belonging to the NR1 subfamily of nuclear receptors. The PPARs play key roles in the control of glucose and lipid homeostasis, and the synthetic isoform-specific PPAR agonists are used clinically to improve insulin sensitivity and to lower serum triglyceride levels. All of the previously reported PPAR agonists form the same characteristic interactions with the receptor, which have been postulated to be important for the induction of agonistic activity. Here we describe a new class of PPARalpha/gamma modulators, the 5-substituted 2-benzoylaminobenzoic acids (2-BABAs). As shown by x-ray crystallography, the representative compounds BVT.13, BVT.762, and BVT.763, utilize a novel binding epitope and lack the agonist-characteristic interactions. Despite this, some compounds within the 2-BABA family are potent agonists in a cell-based reporter gene assay. Furthermore, BVT.13 displays antidiabetic effects in ob/ob mice. We concluded that the 2-BABA binding mode can be used to design isoform-specific PPAR modulators with biological activity in vivo.
Subject(s)
Benzoates/pharmacology , Epitopes/chemistry , Receptors, Cytoplasmic and Nuclear/agonists , Transcription Factors/agonists , Animals , Benzophenones/chemistry , Crystallography, X-Ray , Dose-Response Relationship, Drug , Genes, Reporter , Glucose/metabolism , Hypoglycemic Agents/pharmacology , Ligands , Lipid Metabolism , Male , Mice , Mice, Inbred C57BL , Models, Chemical , Models, Molecular , Protein Binding , Protein Isoforms , Rosiglitazone , Thiazolidinediones/pharmacology , Transcriptional Activation , Triglycerides/bloodABSTRACT
11 beta-Hydroxysteroid dehydrogenase type 1 (11 beta-HSD1) has been proposed as a new target for type 2 diabetes drugs. The aim of the present study was to assess the effects of inhibition of 11 beta-HSD1 on blood glucose levels, glucose tolerance, and insulin sensitivity in mouse models of type 2 diabetes. BVT.2733 is an isoform-selective inhibitor of mouse 11 beta-HSD1. Hyperglycemic and hyperinsulinemic ob/ob, db/db, KKAy, and normal C57BL/6J mice were orally administered BVT.2733 (200 mg/kg.d, twice daily). In hyperglycemic, but not in normal mice, BVT.2733 lowered circulating glucose (to 50-88% of control) and insulin (52-65%) levels. In oral glucose tolerance tests in ob/ob and KKAy mice, glucose concentrations were 65-75% of vehicle values after BVT.2733 treatment, and in KKAy mice insulin concentrations were decreased (62-74%). Euglycemic, hyperinsulinemic clamps demonstrated decreased endogenous glucose production (21-61%). Analysis of hepatic mRNA in KKAy mice showed reduced phosphoenolpyruvate carboxykinase mRNA (71%). A slight reduction in food intake was observed in ob/ob and KKAy mice. Cholesterol, triglycerides, and free fatty acid levels were decreased to 81-86% in KKAy mice after a 4-h fast. The results support previous suggestions that selective 11 beta-HSD1 inhibitors lower blood glucose levels and improve insulin sensitivity in different mouse models of type 2 diabetes.
