Guo Ming-Yu, Satoh Keitaro, Qi Bing, Narita Takanori, Katsumata-Kato Osamu, Matsuki-Fukushima Miwako, Fujita-Yoshigaki Junko, Sugiya Hiroshi
Department of Physiology, Nihon University School of Dentistry at Matsudo, Chiba, Japan.
Biomed Res. 2010 Oct;31(5):293-9. doi: 10.2220/biomedres.31.293.
In parotid acinar cells, the activation of β-adrenergic receptors induces the accumulation of intracellular cAMP, and consequently provokes the exocytotic release of amylase, a digestive enzyme. The cellular redox status plays a pivotal role in regulating various cellular functions. Cellular redox imbalance caused by the oxidation of cellular antioxidants, as a result of oxidative stress, induces significant biological damage. In this study, we examined the effects of diamide, a thiol-oxidizing reagent, on amylase release by rat parotid acinar cells. In cells treated with diamide, the formation of cAMP and the release of amylase induced by the β-agonist isoproterenol (IPR) were partially reduced. The inhibitory effect of diamide on the IPR-induced release of amylase could be abrogated by reduced glutathione or dithiothreitol. Diamide had no effect on the amylase release induced by forskolin, an adenylate cyclase activator, or by mastoparan, a heterotrimeric GTPbinding protein activator. In cells treated with diamide, the binding affinity for [(3)H]DHA, but not the number of binding sites, was reduced. These results suggest that β-adrenergic receptor function is reduced by thiol-oxidation, which inhibits amylase secretion by parotid acinar cells.
在腮腺腺泡细胞中，β - 肾上腺素能受体的激活会诱导细胞内cAMP的积累，进而引发淀粉酶（一种消化酶）的胞吐释放。细胞氧化还原状态在调节各种细胞功能中起关键作用。由于氧化应激导致细胞抗氧化剂氧化引起的细胞氧化还原失衡会诱导显著的生物损伤。在本研究中，我们检测了硫醇氧化试剂二酰胺对大鼠腮腺腺泡细胞淀粉酶释放的影响。在用二酰胺处理的细胞中，β - 激动剂异丙肾上腺素（IPR）诱导的cAMP形成和淀粉酶释放部分降低。二酰胺对IPR诱导的淀粉酶释放的抑制作用可被还原型谷胱甘肽或二硫苏糖醇消除。二酰胺对腺苷酸环化酶激活剂福斯高林或异三聚体GTP结合蛋白激活剂马斯托帕兰诱导的淀粉酶释放没有影响。在用二酰胺处理的细胞中，对[³H]DHA的结合亲和力降低，但结合位点数量未减少。这些结果表明，硫醇氧化会降低β - 肾上腺素能受体功能，从而抑制腮腺腺泡细胞的淀粉酶分泌。
