Baldwin K M, Campbell P J, Hooker A M, Lewis R E
Am J Physiol. 1979 Jan;236(1):C30-4. doi: 10.1152/ajpcell.1979.236.1.C30.
The effects of thyroid deficiency (Td) and of chemical sympathectomy (Sx) were studied on marker enzymes of energy metabolism in cardiac muscle of neonatal and of adult rats. Td prevented the normal development of neonatal body weight, relative heart mass, and cardiac levels of cytochrome c (-22%), citrate synthase (-27%), phosphofructokinase (-20%) and Mg2+- and Ca2+-ATPase activity of purified myofibrils (-33%, -44%). Exogenous thyroxin replacement restored those parameters studied to normal with the exception that it persistently elevated citrate synthase activity significantly above normal control levels. Responses similar to those of Td neonates occurred when adult rats were similarly treated. Sx produced no consistent effects on respiratory and glycogenolytic marker enzymes, but caused a 20% reduction in Ca2+-ATPase activity of both neonatal and adult cardiac myofibrils. These findings suggest that cardiac muscle cells require thyroxin for normal growth and enzyme development. Also, Sx may impair cardiac functional capacity by altering Ca2+ activity of actomyosin ATPase.
研究了甲状腺功能减退（Td）和化学性交感神经切除术（Sx）对新生大鼠和成年大鼠心肌能量代谢标记酶的影响。甲状腺功能减退阻碍了新生大鼠体重、相对心脏质量以及细胞色素c（降低22%）、柠檬酸合酶（降低27%）、磷酸果糖激酶（降低20%）和纯化肌原纤维的镁离子和钙离子ATP酶活性（分别降低33%和44%）的正常发育。外源性甲状腺素替代使所研究的这些参数恢复正常，但柠檬酸合酶活性持续显著高于正常对照水平。成年大鼠接受类似处理时，出现了与甲状腺功能减退新生大鼠相似的反应。化学性交感神经切除术对呼吸和糖原分解标记酶没有产生一致的影响，但导致新生和成年心肌肌原纤维的钙离子ATP酶活性降低20%。这些发现表明，心肌细胞的正常生长和酶的发育需要甲状腺素。此外，化学性交感神经切除术可能通过改变肌动球蛋白ATP酶的钙离子活性来损害心脏功能。
