Devor S T, White T P
Department of Human Biodynamics, University of California, Berkeley 94720-4480, USA.
Med Sci Sports Exerc. 1995 May;27(5):674-81.
The purpose was to test hypotheses regarding the affect of thyroid hormone status on development of myosin heavy chain (MHC) protein phenotype in regenerating skeletal muscle. Soleus (SOL) and extensor digitorum longus (EDL) muscle grafts were studied 30 and 60 d following graft operations in eu-, hypo-, and hyperthyroid rats. Hyperthyroidism had a more profound affect on MHC phenotype than did hypothyroidism, and this was noted in SOL grafts more so than EDL grafts. For example, compared with euthyroid hosts at 30 d, SOL grafts from hyperthyroid hosts demonstrated a decrease from 83% to 3% in Type I MHC, and a decrease from 11% to 4% in Type IIa. Furthermore, Type IIx MHC increased from 5% to 12%, and Type IIb MHC increased from 3% to 82%. The change in Type I and IIb MHC noted at 30 d partially or fully reversed to euthyroid values by 60 d, whereas the hyperthyroid-induced differences in Type IIa and IIx were sustained. The adaptation of control muscles to hypo- and hyperthyroidism was qualitatively similar to muscle grafts for all MHC protein isoforms with the exception of Type IIx, which was expressed more so in grafts. For both grafts and control muscles, the adaptive response of MHC phenotype to sustained hyperthyroidism is transient for several of the MHC isoforms.
目的是检验关于甲状腺激素状态对再生骨骼肌中肌球蛋白重链（MHC）蛋白表型发育影响的假说。在甲状腺功能正常、甲状腺功能减退和甲状腺功能亢进的大鼠中，于移植手术后30天和60天研究比目鱼肌（SOL）和趾长伸肌（EDL）肌肉移植物。甲状腺功能亢进对MHC表型的影响比甲状腺功能减退更为显著，且在SOL移植物中比在EDL移植物中更明显。例如，与30天时甲状腺功能正常的宿主相比，甲状腺功能亢进宿主的SOL移植物中I型MHC从83%降至3%，IIa型从11%降至4%。此外，IIx型MHC从5%增至12%，IIb型MHC从3%增至82%。30天时I型和IIb型MHC的变化在60天时部分或完全恢复到甲状腺功能正常时的值，而甲状腺功能亢进诱导的IIa型和IIx型差异持续存在。除IIx型在移植物中表达更多外，对照肌肉对甲状腺功能减退和亢进的适应性在所有MHC蛋白异构体上与肌肉移植物在质量上相似。对于移植物和对照肌肉，几种MHC异构体的MHC表型对持续甲状腺功能亢进的适应性反应是短暂的。
