Sève B, Ballèvre O, Ganier P, Noblet J, Prugnaud J, Obled C
Station de Recherches Porcines, INRA St Gilles, L'Hermitage, France.
J Nutr. 1993 Mar;123(3):529-40. doi: 10.1093/jn/123.3.529.
The effects of a daily porcine somatotropin injection on protein synthesis rate in muscle (longissimus), liver and intestine, as influenced by dietary protein, were investigated in 17 pigs. The measurements were made at wk 3 of treatment following 1 wk for adaptation to the diet and 1 wk for determination of nitrogen balance. The fractional rates of protein synthesis in the muscle, liver and intestine were measured using a flooding dose of L-[1-13C]valine. Positive responses of weight gain and nitrogen balance were observed, primarily at higher dietary protein intake, after porcine somatotropin treatment. As expected, porcine somatotropin-treated pigs had a higher proportion of muscle and less fat. Fractional protein synthesis rate was 16% higher in the liver of porcine somatotropin-treated pigs (P < 0.05). In the longissimus muscle fractional protein synthesis rate increased with porcine somatotropin dose from 3.2 to 3.7%/d and from 4.1 to 5.1%/d at low and high protein intake, respectively (P < 0.05). The effect of dietary protein on fractional protein synthesis rate in longissimus was significant, but there was no porcine somatotropin x protein interaction. Ribonucleic acid concentration followed the same pattern as fractional protein synthesis rate in liver and longissimus. In the duodenal tissue, porcine somatotropin treatment depressed fractional protein synthesis rate (P < 0.05) without an effect of dietary protein and RNA concentration did not change. In porcine somatotropin compared with placebo-treated pigs, plasma glucose, insulin and insulin-like growth factor-I concentrations were elevated whereas plasma thyroxine was depressed and plasma triiodothyronine remained constant. There was no clear effect of dietary protein on plasma hormones. We concluded that, in pigs fed an adequate level of protein, porcine somatotropin stimulates protein synthesis in the liver and the muscle, primarily through increased ribosomal capacity.
在17头猪身上研究了每日注射猪生长激素对肌肉（背最长肌）、肝脏和肠道蛋白质合成率的影响，以及日粮蛋白质对此的影响。在适应日粮1周和测定氮平衡1周后，于治疗第3周进行测量。使用大剂量L-[1-13C]缬氨酸测量肌肉、肝脏和肠道的蛋白质合成分数率。猪生长激素处理后，主要在较高日粮蛋白质摄入量时，观察到体重增加和氮平衡的阳性反应。正如预期的那样，经猪生长激素处理的猪肌肉比例更高，脂肪更少。经猪生长激素处理的猪肝脏中的蛋白质合成分数率高16%（P<0.05）。在背最长肌中，蛋白质合成分数率随猪生长激素剂量增加，在低蛋白和高蛋白摄入量时分别从3.2%/天增加到3.�%/天和从4.1%/天增加到5.1%/天（P<0.05）。日粮蛋白质对背最长肌中蛋白质合成分数率的影响显著，但不存在猪生长激素×蛋白质的相互作用。核糖核酸浓度与肝脏和背最长肌中蛋白质合成分数率的模式相同。在十二指肠组织中，猪生长激素处理降低了蛋白质合成分数率（P<0.05），日粮蛋白质无影响，核糖核酸浓度未改变。与安慰剂处理的猪相比，经猪生长激素处理的猪血浆葡萄糖、胰岛素和胰岛素样生长因子-I浓度升高，而血浆甲状腺素降低，血浆三碘甲状腺原氨酸保持不变。日粮蛋白质对血浆激素无明显影响。我们得出结论，在摄入足够蛋白质水平的猪中，猪生长激素主要通过增加核糖体容量来刺激肝脏和肌肉中的蛋白质合成。
