Expression and significance of Lipin1 and AMPK in hepatic insulin resistance in diet-induced insulin resistance rats

摘要

Background: Lipin1, a lately indentified adipokine, may link obesity with insulin resistance and diabetes. The present study aimed to investigate the changes and significance of lipin1 expression and lipin1-AMPK signaling in diet-induced hepatic insulin resistance. Methods: 24 4-week-old Male Wistar rats were randomly divided into 2 groups: (1) control group (CO), (2) high-fat diet group (HF). Insulin sensitivity was evaluated by hyperinsulinemic-euglycemic clamp technique. The mRNA levels of 1 and 2 subunit of AMPK as well as Lipin1 were measured using Real-time RT-PCR. The activities of AMPK and Akt were evaluated by detection of p-AMPK (Thr-172) and p-Akt (ser473) by Western blot. Results: After treatment of 4 months, HF group showed significantly increased levels of body weight, fasting plasma glucose and insulin levels; Plasma and liver total cholesterol (TC), triglycerides (TG) levels were also markedly elevated; Lipin1 expression at both mRNA and protein levels were significantly deceased. Compared with CO group, the mRNA and protein levels of AMPK1 and AMPK2 were not changed, whereas the p-AMPK (Thr-172) and p-AKT (ser473) levels in liver were significantly decreased in HF group. Conclusions: These findings indicated that the decrease in lipin1 expression and AMPK activation may contribute to hepatic insulin resistance in diet-induced obese rats.