Abstract: As the main active form of vitamin D,1,25(OH)₂D₃ affects adipogenesis of humans and animals,but its role in proliferation and differentiation of porcine adipocytes is unclear.To explore the effects of 1,25(OH)₂D₃ on proliferation and differentiation of porcine preadipocytes,the cells isolated from subcutaneous adipose tissue of 3-5 days piglets were cultured and treated with 0,0.1,1,10,100 and 1 000 nmol/L concentration of 1,25(OH)₂D₃,respectively.The proliferation of preadipocytes cultured for 0,1,2,4,6,8 and 10 d was detected by MTT method.The differentiation and expression levels of PPARγ and FAS mRNA for the preadipocytes at 0,1,2,4,6,8 and 10 d after inducing-differentiation were determined by oil red O staining and Real-time quantitative PCR,respectively.The results showed that 0.1 and 1 nmol/L 1,25(OH)₂D₃ significantly promoted proliferation of porcine preadipocytes (P<0.05),but the concentration of 10-100 nmol/L inhibited the cell proliferation (P<0.05).At the concentration of 0.1 and 1 nmol/L,1,25(OH)₂D₃ markedly inhibited the differentiation of porcine preadipocytes and reduced mRNA expression of PPARγ and FAS (P<0.05).On the contrary,10 and 100 nmol/L 1,25(OH)₂D₃ significantly enhanced differentiation of porcine preadipocytes and increased mRNA expression of PPARγ and FAS (P<0.05).When the concentration was 1 000 nmol/L,it might be toxic to the cells.These results suggested that low concentration of 1,25(OH)₂D₃ could promote the proliferation of porcine preadipocytes,but inhibit differentiation through down-regulating PPARγ expression.High concentration of 1,25(OH)₂D₃ could inhibit the proliferation of the preadipocytes and promote differentiation by up-regulating PPARγ expression.And so,1,25(OH)₂D₃ affected proliferation and differentiation of porcine preadipocytes in a biphasic manner.

Key words: 1,25(OH)₂D₃; pig; preadipocyte; proliferation; differentiation