Leptin is a dose-dependent marker of caloric restriction in adipose tissues located in different parts of the mouse body

We investigated leptin expression in four fat tissues located in different body parts of male mice. In the absence of caloric restriction (CR), the highest relative levels of leptin mRNA were detected in epididymal fat (EF). Lateral abdominal fat (LAF) and subcutaneous fat (SF) had intermediate leptin expression levels, while the lowest leptin mRNA content was revealed in brown adipose tissue (BAT). We also investigated differential regulation of leptin expression in these adipose tissues following diets that were based on various levels of CR for 10 weeks. The largest reduction of leptin mRNA levels by CR was observed in adipose tissue where maximal leptin mRNA expression was detected in the absence of CR. Leptin protein expression was also decreased by CR as revealed by immunohistochemistry. The changes in leptin mRNA and protein expression positively correlated with adipocyte size that was also diminished with the increase in the strength of CR.