Muñoz Marina C, Giani Jorge F, Dominici Fernando P
Instituto de Química y Fisicoquímica Biológicas , Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Argentina.
Regul Pept. 2010 Apr 9;161(1-3):1-7. doi: 10.1016/j.regpep.2010.02.001. Epub 2010 Feb 25.
The in vivo effect of angiotensin (ANG)-(1-7) on the activation of insulin signaling transduction in rat extracardiac tissues is unknown. Thus, in the present study, we evaluated the ability of ANG-(1-7) to stimulate the phosphorylation of Akt, a main mediator of insulin action in rat extracardiac tissues (adipose tissue, liver and skeletal muscle). We proved that ANG-(1-7) induces the phosphorylation of Akt at both threonine 308 and serine 473 in all tissues analyzed. Selective antagonism of the Mas receptor with A779 blocked the ANG-(1-7)-induced Akt phosphorylation in extracardiac tissues. Reinforcing this evidence, we determined that ANG-(1-7) induces the in vivo activation of the downstream target of Akt, glycogen synthase kinase-3beta in liver and skeletal muscle. Moreover, in every tissue analyzed, the presence of the Mas receptor was detected by immunohistochemical analysis. Based on the current results, we postulate that ANG-(1-7) could be a positive physiological contributor to the actions of insulin in extracardiac tissues. Therefore, our findings extend the possibilities for new approaches in the study of ANG-(1-7)/Mas receptor axis and show the therapeutic potential of ANG-(1-7) in the treatment of metabolic disorders such as insulin resistance as well as other disorders associated with diminished Akt activity.
血管紧张素(ANG)-(1-7)对大鼠心外组织中胰岛素信号转导激活的体内作用尚不清楚。因此,在本研究中,我们评估了ANG-(1-7)刺激Akt磷酸化的能力,Akt是大鼠心外组织(脂肪组织、肝脏和骨骼肌)中胰岛素作用的主要介质。我们证明,ANG-(1-7)在所有分析的组织中均能诱导苏氨酸308和丝氨酸473位点的Akt磷酸化。用A779对Mas受体进行选择性拮抗可阻断心外组织中ANG-(1-7)诱导的Akt磷酸化。进一步证实这一证据的是,我们确定ANG-(1-7)可诱导肝脏和骨骼肌中Akt的下游靶点糖原合酶激酶-3β的体内激活。此外,通过免疫组织化学分析在每个分析的组织中检测到了Mas受体的存在。基于目前的结果,我们推测ANG-(1-7)可能是心外组织中胰岛素作用的一种正向生理促进因子。因此,我们的研究结果扩展了ANG-(1-7)/Mas受体轴研究新方法的可能性,并显示了ANG-(1-7)在治疗代谢紊乱(如胰岛素抵抗)以及其他与Akt活性降低相关疾病方面的治疗潜力。