Griffiths R I, Baldwin J, Berger P J
Institute of Reproduction and Development, Monash Medical Centre, Clayton, Victoria, Australia.
Respir Physiol. 1994 Mar;95(3):337-47. doi: 10.1016/0034-5687(94)90096-5.
Several parameters indicative of whole muscle aerobic and anaerobic metabolism were compared in heart, diaphragm and two locomotory muscles of sheep (Ovis aries) ranging from 90 days gestation to adult animals. Aerobic metabolism was assessed from myoglobin content, anaerobic metabolism from the pH buffering capacity and the balance between the two from the properties of the lactate dehydrogenase isozymes. We expected the diaphragm and heart, as the two vital pumps of the body, to have substantial aerobic capacity at birth. For the left ventricular myocardium this appears to be true, with the myoglobin level at birth averaging 69% of the adult value. However, the diaphragm had only 15% of the adult myoglobin level, a level similar to that in vastus lateralis and medial gastrocnemius muscles. In the first 18 days postnatally, myoglobin levels in the diaphragm did not change. Anaerobic capacity, as indicated by pH buffering capacity, increased in all four muscles during fetal life, reaching from 69-96% of adult values on day 1 after birth. A rapid increase in pH buffering capacity occurred in all four muscles in the first 6 days postnatally suggesting that anaerobic glycolysis is important to the newborn. We conclude that the work done by the fetal heart leads to the development of a high aerobic capacity by birth, but the activity of the fetal diaphragm does not have this effect.
在从妊娠90天到成年的绵羊（Ovis aries）中，比较了心脏、膈肌和两块运动肌肉中几个指示全肌肉有氧和无氧代谢的参数。通过肌红蛋白含量评估有氧代谢，通过pH缓冲能力评估无氧代谢，并通过乳酸脱氢酶同工酶的特性评估两者之间的平衡。我们预期膈肌和心脏作为身体的两个重要泵，在出生时具有相当大的有氧能力。对于左心室心肌来说似乎确实如此，出生时肌红蛋白水平平均为成年值的69%。然而，膈肌的肌红蛋白水平仅为成年水平的15%，这一水平与股外侧肌和腓肠肌中的水平相似。在出生后的前18天，膈肌中的肌红蛋白水平没有变化。以pH缓冲能力表示的无氧能力在胎儿期所有四块肌肉中都有所增加，出生后第1天达到成年值的69 - 96%。出生后前6天所有四块肌肉的pH缓冲能力都迅速增加，这表明无氧糖酵解对新生儿很重要。我们得出结论，胎儿心脏的工作导致出生时具有高有氧能力的发育，但胎儿膈肌的活动没有这种效果。
