Leptin is an adipocyte-derived hormone/cytokine that links nutritional status and hypothesized to function as a negative feedback signal in the regulation of energy balance.Some studies on ketosis and leptin were reported but the leptin and its receptors genes expression in vitro in adipose tissue after β-hydroxybutyric acid (BHBA) stimulation remains limited.To understand effect of BHBA, leptin and insulin on mRNA expression of leptin and its receptor in different adipose depots of calf in vitro, following tests were conducted.mRNA expression of leptin, ObRa, ObRb and ObRc were detected in subcutaneous adipose, mesenteric adipose and perirenal adipose tissues which were respectively treated with different concentrations of BHBA (0.5, 1.0, 3.0, 5.0 mmol/L), leptin (10, 50, 100 ng/mL) and insulin (10, 50, and 100 nmol/L).mRNA expression of ObRa was not found in the above adipose tissues.Subcutaneous adipose was the most sensitive to BHBA.The lower dose of BHBA (0.5, 1.0 mmol/L) was significantly up-regulated mRNA expression of leptin, ObRb and ObRc (P < 0.05).The higher dose of BHBA (3.0, 5.0 mmol/L) downregulated mRNA expression of leptin, moreover significantly reduced the upregulated effect on ObRb and ObRc.In perirenal adipose ObRc was the only one could respond to the change of BHBA concentration.Regulation on leptin and leptin receptor genes with each concentration of leptin was shown to be a point of convergence in subcutaneous adipose and perirenal adipose tissue.In subcutaneous adipose gene leptin,ObRb, ObRc transcriptional level decreased with the increase of insulin concentration, in perirenal adipose they acted in an opposite way.All three medicines downregulated above three mRNA in mesenteric adipose, among them, insulin had a significant effect (P<0.05).In conclusion, different concentration of BHBA can directly effect on leptin-related genes transcription.The mRNA level of leptin in different adipose depots was varied, the subcutaneous adipose which had the greatest sensitivity to BHBA, might be the main spot of leptin synthesis and secretion.In perirenal adipose tissue, leptin-related genes transcription was not much changed and maintained at an acceptable level.