Department of Movement, Human and Health Sciences, Section of Health Sciences, University of Rome "Foro Italico", 00135 Rome, Italy.
J Endocrinol Invest. 2013 Dec;36(11):1020-6. doi: 10.3275/9034. Epub 2013 Jul 15.
Phosphodiesterase type 5 inhibitors (PDE5i), widely used to treat male erectile dysfunction, seem to counteract insulin resistance (IR) in animals and humans. IR, primarily manifest in peripheral tissues and particularly in skeletal muscle, is due to impaired insulin signal transduction. Investigators have been focusing onto intracellular defects responsible for IR to identify suitable pharmacological tools targeted toward the specific defects. Albeit some effects of PDE5i have been reported onto animal muscular tissues or cells, whether and how they might affect metabolic processes directly in human skeletal muscle still remains unclear.
We aimed to investigate in human fetal skeletal muscle cells (Hfsmc) the effect of tadalafil, one of PDE5i, onto some intracellular factors involved in response to insulin, such as ras-raf mitogen activated protein kinase (MAPK), phosphatidylinositol 3-kinase/protein kinase B (PKB/Akt), glycogen synthase kinase 3β (GSK-3β), and the transcriptional factor c-Myc; proliferation rate; lactate (lact) and free fatty acid (ffa) release; activity of citrate synthase (CS) and succinate dehydrogenase (SDH), both enzymes of Kreb's cycle; PDE5 gene expression.
Western blot analysis, enzyme-linked immunosorbent assay, enzymatic assays, cell count, MTT assay and Real Time PCR were performed in Hfsmc with and without tadalafil.
In Hfsmc tadalafil affected the insulin-related intracellular cascade, by increasing MAPK, PKB/Akt, GSK-3β phosphorylation and c-Myc expression. ffa release and CS activity also significantly increased, with no changes in SDH activity and lact release.
Tadalafil, like insulin, targeted part of the machinery dedicated to energy management and metabolic control in human skeletal muscle cells.
磷酸二酯酶 5 抑制剂（PDE5i）被广泛用于治疗男性勃起功能障碍，似乎可以在动物和人类中对抗胰岛素抵抗（IR）。IR 主要表现在外周组织中，特别是在骨骼肌中，是由于胰岛素信号转导受损引起的。研究人员一直专注于导致 IR 的细胞内缺陷，以确定针对特定缺陷的合适药物工具。尽管已经报道了 PDE5i 对动物肌肉组织或细胞的一些影响，但它们是否以及如何直接影响人类骨骼肌的代谢过程仍不清楚。
我们旨在研究 PDE5i 之一他达拉非对胰岛素反应中一些细胞内因子（如 ras-raf 丝裂原活化蛋白激酶（MAPK）、磷脂酰肌醇 3-激酶/蛋白激酶 B（PKB/Akt）、糖原合酶激酶 3β（GSK-3β）和转录因子 c-Myc）、增殖率、乳酸（lact）和游离脂肪酸（ffa）释放、柠檬酸合酶（CS）和琥珀酸脱氢酶（SDH）活性（克雷布斯循环中的两种酶）、PDE5 基因表达在人胎儿骨骼肌细胞（Hfsmc）中的影响。
在存在和不存在他达拉非的情况下，通过 Western blot 分析、酶联免疫吸附测定、酶促测定、细胞计数、MTT 测定和实时 PCR 在 Hfsmc 中进行了上述实验。
在 Hfsmc 中，他达拉非通过增加 MAPK、PKB/Akt、GSK-3β磷酸化和 c-Myc 表达来影响与胰岛素相关的细胞内级联反应。ffa 释放和 CS 活性也显著增加，而 SDH 活性和 lact 释放没有变化。
他达拉非与胰岛素一样，靶向人类骨骼肌细胞中用于能量管理和代谢控制的部分机制。
