促黑素促进骨骼肌细胞脂肪酸氧化中cAMP的作用

Effect of cAMP on fatty acid oxidation in skeletal muscle cells byα-MSH

目的:探讨骨胳肌细胞中环磷酸腺苷(cAMP)对脂肪酸氧化的影响,阐明促黑素(α-MSH)对脂肪酸氧化影响的作用机制。方法:采用α-MSH、cAMP类似物Bt2cAMP、8-BrcAMP和cAMP拮抗剂分别处理体外培养的原代骨骼肌细胞(PMC)和C2C12成肌细胞,分为α-MSH组、cAMP类似物组、cAMP拮抗剂加α-MSH组,同时设正常对照组,利用(9,10-3H)棕榈酸生成3H2O的方法测定脂肪酸氧化。RT-PCR法测定PMC和C2C12成肌细胞黑皮质素受体(MCR)的表达。结果:α-MSH组和cAMP类似物组与对照组比较脂肪酸氧化显著增加(P<0.05);cAMP拮抗剂RpcAMP预处理组细胞脂肪酸氧化率明显降低,与对照组比较差异无显著性(P>0.05),与α-MSH组比较差异有显著性(P<0.05)。结论:α-MSH和cAMP类似物显著增加了脂肪酸氧化,α-MSH可能与MCR结合通过cAMP信号传导通路促进骨骼肌细胞的脂肪酸氧化。

Objective To investigate the effect of cAMP on fatty acid oxidation in skeletal muscle cells and elucidate the mechanism of the effect of cyclic AMP （cAMP）on fatty acid oxidation in skeletal muscle.Methods The primary muscle cells（PMC）and C2C12cells were treated withα-MSH,cAMP analogs Bt2cAMP,8-BrcAMP and cAMP antagonist respectively,and they were divided intoα-MSH group,cAMP agonists group,cAMP antagonist plusα-MSH group,and control group was set up at the same time.The fatty acid oxidation was measured by quantitating the production of 3 H2O from （9,10-3 H）palmitate.Melanocortin receptor（MCR）subtypes in the muscle and C2C12cells were measured by RT-PCR.Results The fatty acid oxidation was significantly increased in cAMP analogs group andα-MSH group compared with control group （P0.05）,and the fatty acid oxidation in cAMP antagonist plusα-MSH group was significantly reduced compared withα-MSH group（P0.05）,and there was no significant difference compared with control group （P0.05）.Conclusion α-MSH and cAMP analogs significantly increase the fatty acid oxidation,α-MSH might be binding with MCR and they increase fatty acid oxidation in skeletal muscle through cAMP signal transduction pathway.