Larsson L, Sjödin B, Karlsson J
Acta Physiol Scand. 1978 May;103(1):31-9. doi: 10.1111/j.1748-1716.1978.tb06187.x.
Biopsies for histochemical and biochemical analyses were taken from the vastus lateralis muscle of 55 untrained, healthy male subjects from 22 to 65 years of age. Fibre type distribution changed towards a decrease in the percentage of type II fibres, both in type IIA and type IIB fibres, whereas type IIB/IIA fibre ratio and type IIC percentage did not change with increasing age. It was found that the type IIB/IIA fibre ratio was inversely related to type I fibres, i.e. subjects rich in type I fibres had a relatively smaller proportion of type IIB fibres. Fibre area determinations revealed a selective decrease in type II fibre area. Consequently, the type II/I fibre area ratio and relative type II fibre area decreased. No changes in the specific activities of Mg2+ stimulated ATPase and myokinase were observed, while the activity of lactate dehydrogenase (LDH) was higher in the youngest groups than in the oldest. LDH isozyme pattern shifted towards a decrease in percentage distribution of the muscle specific isozymes and a corresponding decrease in muscle specific activity while the activity of the heart specific isozymes did not change.
对55名年龄在22至65岁之间未经训练的健康男性受试者的股外侧肌进行活检，用于组织化学和生化分析。纤维类型分布向II型纤维百分比下降的方向变化，IIA型和IIB型纤维均如此，而IIB/IIA型纤维比例和IIC型百分比并未随年龄增长而改变。研究发现，IIB/IIA型纤维比例与I型纤维呈负相关，即富含I型纤维的受试者IIB型纤维比例相对较小。纤维面积测定显示II型纤维面积选择性减少。因此，II/I型纤维面积比和相对II型纤维面积降低。未观察到Mg2+刺激的ATP酶和肌激酶的比活性有变化，而乳酸脱氢酶（LDH）的活性在最年轻组高于最年长组。LDH同工酶模式向肌肉特异性同工酶百分比分布减少以及相应的肌肉特异性活性降低的方向转变，而心脏特异性同工酶的活性未改变。
