Ontogeny of insulin binding during chick skeletal myogenesis in vitro☆
[摘要] Ourstudiesshowthatinsulinreceptorsexistonchickenskeletalmusclecellsatalldevelopmentalstagesinculture.125I-labeledinsulinbindingatphysiologicalconcentrationstomaturemyotubesdemonstratedsaturability,bindingproportionaltocellnumber,reversibility,andspecificitybycompetitionwithnativehormonewhichreducedspecificbindingby40%with1ng/mlandwasmaximalwith10μg/ml.FurtherevidenceforspecificitywasshownbynocompetitionofinsulinspecificbindingwithinsulinAchain,insulinBchain,growthhormone,andthyrotropin.Twobindingsitesweredetected,withaffinityconstantsof1010M−1and2×109M−1.Thehormonereceptorcomplexshowedrapiddissociation(70%in30min)afterequilibriumbinding.Duringmyogenesis,anincreaseininsulinreceptorsoccursfrom500perproliferatingmyoblastto3000percellequivalentinmature(6day)myotubes.Sincethesestudiesdemonstratethatinsulinreceptorsarepresentandotherstudieshaveshownthatinsulinispresentduringmostofchickenembryogenesis,insulinmayregulatemuscledevelopmentinvivotoagreaterdegreethanpreviouslysuspected.
[发布日期] [发布机构]
[效力级别] [学科分类] 生物科学（综合）
[关键词] [时效性]
