| Objective: To investigate the effects of Exendin-4 on differentiation of 3T3-L1 preadipocytes and mRNA expressions of GLUT-4,PPAR-γand HSL.Methods: 3T3-L1 preadipocytes of different differentiation stages were treated by Exendin-4. Morphological changes of 3T3-L1 preadipocytes and cell differentiation were measured by inverted phase contrast mocroscope. The number of lipid droplets was observed by Oil red O staining. The mRNA expressions of GLUT-4,PPAR-γand HSL were detected by quantitative real-time polymerase chain reaction(RT-PCR).The triglyceride content of 3T3-L1 preadipocytes was quantitated with an acetyl acetone–based colorimetric kit.Results: Induced differentiation of mature adipocytes showed large lipid droplets of red within the cytoplasm by oil red O staining, undifferentiated cells are not stained by oil red O.Comparing with control group, Exendin-4 promoted preadipocyte differentiation, increased TG content (P<0.01) and the mRNA expression of GLUT-4, HSL and PPAR-γ(P<0.01) when treated with Exendin-4 at day 0.Compared with the control group,TNF-αsignificantly reduced mRNA expressions of GLUT-4 and HSL (P<0.01). Compared with troglitazone group, the expressions of PPAR-γmRNA reduced in EX-4 group (P<0.05), the expressions of GLUT-4 and HSL mRNA significantly increased (P<0.01) and the expressions of PPAR-γmRNA increased (P<0.05) in Ex-4 combined with troglitazone group.Comparing with control group, Exendin-4 promoted preadipocyte differentiation, increased TG content (P<0.01) and the mRNA expressions of GLUT-4, HSL andPPAR-γ(P<0.01) when treated with Exendin-4 at day 6. Compared the control group, TNF-αgroup significantly reduced GLUT-4 and HSL mRNA expressions (P<0.01) and reduced PPAR-γmRNA expression (P<0.05); Compared with Troglitazone group , the expressions of GLUT-4 mRNA reduced in Ex-4 group (P<0.05) and the expression of HSL mRNA significantly reduced (P<0.01). Compared with Troglitazone group, the expressions of HSL and PPAR-γmRNA increased in Ex-4 combined with troglitazone group (P <0.05).Compared with control group, the expressions of GLUT-4 mRNA increased in Ex-4 combined with troglitazone group and Trogli group(P<0.05). Compared with control group, the expressions of HSL mRNA reduced in TNF-αgroup (P<0.01) when treated with Exendin-4 at day. Compared with Troglitazone group, the expressions of GLUT-4 and HSL mRNA reduced in Ex-4 group (P<0.05), Compared with Troglitazone group, increased TG content (P<0.01) and the mRNA expression of HSL mRNA increased in Ex-4 combined with troglitazone group (P<0.05) and TG content also increased (P<0.05).Conlusion: Exendin-4 promoted adipocyte differentiation,increased glucose and lipid metabolism related genes mRNA expression, which may be some new mechanisms of Exendin-4 anti-diabetic. |
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