Insulin target gene expression during weight loss in obese and insulin resistant dogs

• Published in: The FASEB journal 2007-04, Vol.21 (5), p.A5-A5
• Main Authors: Leray, Veronique, Serisier, Samuel, Khoshniat, Solmaz, Nguyen, Patrick
• Format: Article
• Language: English
• ISSN: 0892-6638; 1530-6860
• DOI: 10.1096/fasebj.21.5.A5-a

Body weight (BW) depends especially on a balance between lipogenesis and lipolysis. It could influence insulin sensitivity (IS), leading to inhibition of lipogenesis and stimulation of lipolysis. The aim of this study was to evaluate the effect of weight loss on IS and expression of genes involved in lipogenesis and lipolysis in insulin target tissues in dogs. Obese dogs were given a hypoenergetic diet. Before and after weight loss, IS was assessed using the euglycemic hyperinsulinemic clamp. Gene expression of IRS‐2, SREBP (insulin effectors), ACC, FAS, FABP, ADRP, PEPCK (lipogenesis proeins), and perilipin and HSL (lipolysis proteins), was quantified using real time RT‐PCR in subcutaneous and visceral fat, and liver. Dog weight decreased by 25 % over 78 ± 8 days. After weight loss, IS was higher. In the subcutaneous fat, the expression of only the IRS‐2 increased. In the visceral fat, the expression of IRS2 was higher, that of lipogenesis genes was lower and that of lipolysis genes did not change. In liver, the expression of IRS2 and HSL was higher and that of perilipin was lower. Lipogenesis gene expression was lower, except FABP. These results show that, in visceral fat, lipogenesis is lower during weight loss, and in liver, lipolysis is higher They also confirm differences between fat tissues and liver in the response of lipid metabolism insulin action.