Effect Of Obestatin On Proliferation And Differentiation Of 3T3-L1 Preadipocyte And The Related Mechanism

Objective To investigate the effect of obestatin on proliferation and differentiation of 3T3-L1 preadipocyte and explore the related mechanism. Methods Various concentrations of obestatin (10-8 mmol/l,10-9 mmol/l,10-10 mmol/l,10-11 mmol/l,10-12 mmol/l) were added to the culture media of 3T3-L1 preadipocyte. Cell proliferation was determined by MTT assay and glucose consumption test. The differentiated 3T3-L1 adipocytes were incubated with 10-10 mmol/l obestatin. Intracellular fat accumulation was determined by oil red O staining. The expression of PPARγ2 mRNA were detected by RT-PCR. The expression of PTP1B mRNA was detected by RT FQ-PCR. The expression of PTP1B protein was detected by Western-blot. Phosphorylation of insulin receptorβsubunit was examinated by immunopricipitate and Western-blot. Results①The absorbance at 570nm in various concentrations of obestatin-treated groups were significantly reduced compared with the control group.②Oil red O staining revealed that the formation of lipid droplets was significantly decreased by 10-10mmol/l obestatin.③The expression of PPARγ2 gene increased with the differentiation period of 3T3-L1 preadipocytes to adipocytes. With stimulation of 10-10 mmol/l obestatin, the PPARγ2 mRNA level was significantly decreased compared with the control group.④The expression of PTP1B gene decreased with the differentiation period of 3T3-L1 preadipocytes to adipocytes. With stimulation of 10-10 mmol/l obestatin, the PTP1B mRNA and protein level was significantly increased compared with the control group.⑤Compared with the control group,phosphorylation of insulin receptorβsubunit in obestatin-treated group was significantly inhibited. Conclusions Obestatin inhibits the proliferation and differentiation of 3T3-L1 preadipocye. The effect is mediated by the upregulated PTP1B level and its effect on phosphorylation of insulin receptor.