Laboratório de Endocrinologia Experimental e Eletrofisiologia, Departamento de Fisiologia, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite 500, sala 212, Porto Alegre, Rio Grande do Sul, Brazil, 90050-170.
Pflugers Arch. 2013 Oct;465(10):1497-505. doi: 10.1007/s00424-013-1287-z. Epub 2013 May 1.
There is clear evidence that insulin and insulin-like growth factor I (IGF-I) are crucial for the normal metabolism and development of Sertoli cells. However, the mechanisms of insulin regulatory signaling remain unknown in these cells, especially during the immature period. The aim of this study was to investigate the electrophysiological effects of insulin and the effects of insulin and IGF-I on calcium uptake, amino acid, and glucose transport in whole seminiferous tubules from 12-day-old rats, as well as the involvement of PI3K/Akt signaling pathway in these effects. Insulin produces a depolarizing effect on the membrane potential of Sertoli cells in seminiferous tubules within 180 s. This effect was nullified by verapamil, an L-type voltage-dependent calcium channel blocker, therefore demonstrating a calcium-dependent depolarizing effect. Both insulin and IGF-I stimulate calcium uptake, amino acid, and glucose transport in whole testes from 12-day-old rats. These stimulatory effects of insulin and IGF-I on calcium uptake and amino acid and glucose transport on testicular tissue were nullified by wortmannin, which demonstrates the involvement of the PI3K/Akt signaling pathway in these hormonal effects.
有明确的证据表明，胰岛素和胰岛素样生长因子 I（IGF-I）对支持细胞的正常代谢和发育至关重要。然而，在这些细胞中，胰岛素调节信号的机制仍然未知，尤其是在不成熟阶段。本研究旨在探讨胰岛素对整个 12 日龄大鼠睾丸曲细精管中支持细胞的膜电位的电生理作用，以及胰岛素和 IGF-I 对钙摄取、氨基酸和葡萄糖转运的影响，同时还研究了 PI3K/Akt 信号通路在这些作用中的参与情况。胰岛素在 180 秒内对曲细精管中支持细胞的膜电位产生去极化作用。维拉帕米是一种 L 型电压依赖性钙通道阻滞剂，这种去极化作用可被维拉帕米阻断，因此证明了胰岛素的去极化作用依赖于钙。胰岛素和 IGF-I 均能刺激 12 日龄大鼠整个睾丸的钙摄取、氨基酸和葡萄糖转运。wortmannin 可使胰岛素和 IGF-I 对钙摄取以及氨基酸和葡萄糖转运的刺激作用失效，这表明 PI3K/Akt 信号通路参与了这些激素的作用。
