Prewitt T E, D'Ercole A J, Switzer B R, Van Wyk J J
J Nutr. 1982 Jan;112(1):144-50. doi: 10.1093/jn/112.1.144.
Protein-energy undernutrition has its most devastating consequences during growth. Postal somatic growth now appears to be regulated in large part by the somatomedins, a family of growth hormone-dependent peptide mitogens. This study, using growing rats as the model, was designed to determine the relationship between protein and energy intake and serum immunoreactive somatomedin-C. Four-week-old male Sprague-Dawley rats were fed ad libitum three levels of isoenergetic protein diets (5%, 10%, and 15% lactalbumin) at each of three levels of energy (ad libitum, 75% or 50% of ad libitum quantities). Dietary fat was held constant at 11.9% as cottonseed oil. At 5 weeks of age, serum somatomedin-C concentration was predominately influenced by the dietary protein and increased linearly as protein intake increased from 5% to 15%. at 6, 9, and 12 weeks of age, serum somatomedin-C concentration was influenced by both protein and energy intake, although protein intake appeared to be the more important variable. Serum somatomedin-C was highly correlated with both body weight (r = 0.84, P less than 0.001) and tail length (r = 0.74, P less than 0.01). These results indicate that measurement of immunoreactive somatomedin-C provides a valuable biochemical index of protein-energy nutriture.
蛋白质-能量营养不良在生长期间会产生最具破坏性的后果。目前看来，体格生长在很大程度上受生长调节素的调控，生长调节素是一类依赖生长激素的肽类促细胞分裂剂。本研究以生长中的大鼠为模型，旨在确定蛋白质和能量摄入量与血清免疫反应性生长调节素C之间的关系。给四周龄的雄性斯普拉-道来大鼠随意喂食三种能量水平（随意摄入量、随意摄入量的75%或50%）下的三种等能量蛋白质日粮（5%、10%和15%的乳白蛋白）。膳食脂肪以棉籽油形式保持在11.9%不变。在5周龄时，血清生长调节素C浓度主要受膳食蛋白质的影响，并随着蛋白质摄入量从5%增加到15%而呈线性增加。在6周龄、9周龄和12周龄时，血清生长调节素C浓度受蛋白质和能量摄入量两者的影响，尽管蛋白质摄入量似乎是更重要的变量。血清生长调节素C与体重（r = 0.84，P < 0.001）和尾长（r = 0.74，P < 0.01）均高度相关。这些结果表明，免疫反应性生长调节素C的测定提供了一种有价值的蛋白质-能量营养状况的生化指标。
