To identify the effect of leptin on adipocyte, preadipocyte was isolated from male dairy calves and cultured in a monolayer; 5？μg·L？1 bovine leptin were added in culture liquid when the cell differentiated into adipocytes. The result showed that leptin decreased the deposition of triglyceride (TG) and increased the levels of hormone sensitive lipase (HSL) mRNA in cells. At the same time, leptin suppressed the levels of endogenous leptin mRNA, and the levels of leptin receptor (Ob-R) mRNA were raised significantly. It indicated that leptin may induce more fat metabolism directly.
