Additive action of 11beta-HSD1 inhibition and PPAR-gamma agonism on hepatic steatosis and triglyceridemia in diet-induced obese rats.

Both 11beta-hydroxysteroid dehydrogenase (11beta-HSD1) inhibition and peroxisome proliferator-activated receptor-gamma (PPAR-gamma) agonism reduce liver and plasma lipids in rodents through partly distinct mechanisms. This study aimed to assess their additivity of action on liver and plasma lipids in a model of diet-induced steatosis. Rats were fed an obesogenic diet and were treated either with an 11beta-HSD1 inhibitor (Compound A, 3 mg kg(-1) day(-1)) or rosiglitazone (RSG, 5 mg kg(-1) day(-1)) or both for 6 weeks. Compound A and RSG reduced liver steatosis and triglyceridemia, and did so additively when given in combination. The 11beta-HSD1 inhibitor had no effect on serum adiponectin, but increased liver adiponectin receptor type 2 (Adipo-R2) mRNA levels. Conversely, RSG increased serum adiponectin, a likely mediator of its antisteatotic action, but had no effect per se on the Adipo-R2 expression. mRNA levels of representative genes of fatty acid oxidation tended to be increased by both compounds. The study shows that combined 11beta-HSD1 inhibition and PPAR-gamma agonism additively reduce liver steatosis and triglyceridemia, which may eventually prove therapeutically useful.