Abstract: Objective: To study the effect of different protein intakes on the adiponectin signaling pathway in the liver of overweight male SD rats with low energy intake. Methods: Six out of 36 rats were randomly selected as normal control group (NC), and the rest were given a high-fat diet. After 9 weeks of feeding, 16 rats with average body mass over 1.1 times heavier than that of the normal diet group were selected and equally randomized into model control (MC), low-energy, low-protein (LP), low-energy, normal-protein (NP), low-energy, high-protein (HP) groups before being subjected to energy and protein controlled feeding for 9 weeks. During the experimental period, body mass, body fat mass, liver mass, liver fat mass, serum adiponectin (APN) concentration, and the levels of liver AMP-activated protein kinase (AMPK), sterol regulatory element binding protein 1c (SREBP-1c), acetyl-CoA carboxylase (ACC), fatty acid synthetase (FAS), peroxisome proliferators-activated receptors α (PPARα) and carnitine palmitoy transferase-1 (CPT-1) in the rats in each group were determined. Results: After 9 weeks of intervention, compared with the MC group, body fat mass, liver mass, liver fat mass, and liver SREBP-1c, ACC and FAS levels in the three intervention groups were significantly reduced (P < 0.05), and serum APN level and liver AMPK, PPARα and CPT-1 levels were significantly increased (P < 0.05). There was no significant difference in body mass, body fat mass, liver mass or liver AMPK level among the intervention groups (P > 0.05). Compared with the LP and NP groups, liver fat mass in the HP group was significantly reduced (P < 0.05), and serum APN and liver SREBP-1c, ACC, FAS, PPAR α and CPT-1 levels were increased significantly (P < 0.05). Conclusion: After energy control, the levels of various factors in the signaling pathways of APN-AMPK and APN-PPARα-CPT-1 in the liver of overweight rats were significantly increased (P < 0.05), thereby reducing body mass, liver mass and liver fat mass to some extent. In the case of consistent energy restriction, high protein intake can promote the activation of APN-PPARα signaling pathway, thus reducing live fat mass in overweight rats, while having no significant influence on the body mass, body fat mass or liver mass (P > 0.05).

Key words: adiponectin signaling pathway, protein intake, energy limitation