年龄和断奶对羔羊骨骼肌和内脏肌蛋白质合成的各自影响。

Respective influences of age and weaning on skeletal and visceral muscle protein synthesis in the lamb.

Attaix D, Aurousseau E, Bayle G, Rosolowska-Huszcz D, Arnal M

Laboratoire d'Etude du Métabolisme Azoté, INRA et CNRS UA 1123, Centre de Recherches de Clermont-Ferrand-Theix, Ceyrat, France.

Biochem J. 1988 Dec 15;256(3):791-5. doi: 10.1042/bj2560791.

Abstract

The influences of age and weaning on muscle protein synthesis were studied in vivo, by injecting a large dose of [3H]valine into 1-, 5- and 8-week-old suckling or 8-week-old weaned lambs. 2. The fractional rates of protein synthesis, in red- and white-fibre-type skeletal muscles or striated and smooth visceral muscles, were in 8-week-old suckling animals 24-37% of their values at 1 week of age. This developmental decline was related to decreased capacities for protein synthesis, i.e. RNA/protein ratios. 3. At 8 weeks of age, suckling and weaned lambs had similar fractional synthesis rates, capacities for protein synthesis and efficiencies of protein synthesis (i.e. rates of protein synthesis relative to RNA) in skeletal muscles. 4. In contrast, visceral-muscle fractional synthesis rates were lower in 8-week-old suckling lambs than in weaned animals, owing to decreased efficiencies of protein synthesis. It was concluded that developmental factors and the change to a solid diet, or weaning in itself, or both, affect differently skeletal and visceral muscle protein synthesis in the immature lamb.

摘要

通过向1周龄、5周龄和8周龄的哺乳羔羊或8周龄断奶羔羊注射大剂量的[3H]缬氨酸，在体内研究了年龄和断奶对肌肉蛋白质合成的影响。2. 在8周龄的哺乳动物中，红肌纤维型和白肌纤维型骨骼肌或横纹肌和平滑内脏肌的蛋白质合成分数率为其1周龄时的24%-37%。这种发育性下降与蛋白质合成能力下降有关，即RNA/蛋白质比率。3. 在8周龄时，哺乳羔羊和断奶羔羊在骨骼肌中的蛋白质合成分数率、蛋白质合成能力和蛋白质合成效率（即相对于RNA的蛋白质合成速率）相似。4. 相反，8周龄哺乳羔羊的内脏肌蛋白质合成分数率低于断奶动物，原因是蛋白质合成效率降低。得出的结论是，发育因素以及向固体饮食的转变、断奶本身或两者兼而有之，对未成熟羔羊的骨骼肌和内脏肌蛋白质合成的影响不同。