Decrease in Leptin Expression in the Liver after Prolonged Every-Other-Day Feeding in C57Bl/6 Male Mice

Background: The positive effects of prolonged every-other-day (EOD) feeding include decreased body weight and prolonged life span, but also changes in liver metabolism and functions. In the present paper, our aim was to examine the expression of adiponectin (ADIPOQ), leptin, and their receptors (ADIPOR1, ADIPOR2, and LEPR) in the liver tissue of EOD-fed mice in comparison to ad libitum (AL)-treated mice. Methods: After 9 months of EOD treatment, liver tissue was harvested and prepared for analysis. RT-PCR, protein semi-quantitative estimation, and cellular immunolocalization was performed. Results: We noted a decreased expression of leptin in the liver tissue of the EOD male mice in comparison to the AL mice on the protein level. ADIPOQ receptor R1 protein expression was decreased in the liver of EOD-fed male mice, while the expression of ADIPOR2 on the protein level was increased in the EOD animals. Conclusions: To the best of our knowledge, this is the first report showing ADIPOQ and leptin immunolocalization in the liver tissue in a dietary regime experiment. Decreases in leptin expression and IL-6 expression in liver tissue and increases in ADIPOR2 expression may be partly responsible for the beneficial effects of EOD treatment in the liver, including the decrease in inflammation. Further studies are needed to establish whether these changes depend on factors like the type of treatment, species, strain, gender, time of treatment, and others.