Modulation of growth hormone receptor-insulin-like growth factor 1 axis by dietary protein in young ruminants
Modulation of growth hormone receptor-insulin-like growth factor 1 axis by dietary protein in young ruminants
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DOI：
10.1017/s0007114519003040
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发表时间：
2020-03-28
影响因子：
3.6
通讯作者：
Muscher-Banse, Alexandra S.
中科院分区：
文献类型：
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作者：
Firmenich, Caroline S.;Schnepel, Nadine;Muscher-Banse, Alexandra S.
蛋白质摄入量的减少导致胰岛素样生长因子1(IGF1)浓度的降低，并调节年轻山羊的钙稳态。IGF1是肝脏在生长激素(GH)刺激下合成的。由于尿素的瘤胃-肝脏循环，反刍动物适合研究蛋白质减少的效果，尽管摄入了足够的能量。本研究旨在探讨低蛋白质饮食对促生长轴各成分表达的影响。将雄性青年山羊分为两组，分别饲喂对照日粮(20%粗蛋白)和低蛋白日粮(9%CP)。测量IGF1和GH的血药浓度，并编制24小时GH分泌图谱。此外，离子钙和胰岛素浓度以及参与生长激素信号转导的肝脏蛋白的mRNA和蛋白表达水平也被量化。由于低蛋白质饮食，电离钙、胰岛素和IGF1的浓度显著降低，而生长激素浓度保持不变。肝脏生长激素受体(GHR)的表达水平在蛋白质减少的过程中降低。由于胰岛素浓度降低，生长激素受体表达下调，因为这两个参数呈正相关。胰岛素本身可能由于参与胰岛素释放的血钙水平降低而减少。低蛋白质饮食对促生长轴各成分的表达有影响，因为低蛋白质饮食导致GHR表达减少导致GH-IGF1轴紊乱。
A reduced protein intake causes a decrease in insulin-like growth factor 1 (IGF1) concentrations and modulates Ca homoeostasis in young goats. IGF1 is synthesised by the liver in response to stimulation by growth hormone (GH). Due to rumino-hepatic circulation of urea, ruminants are suitable for investigating the effects of protein reduction despite sufficient energy intake. The present study aimed to investigate the impact of a protein-reduced diet on the expression of components of the somatotropic axis. Male young goats were divided into two feeding groups receiving either a control diet (20 % crude protein (CP)) or a reduced-protein diet (9 % CP). Blood concentrations of IGF1 and GH were measured, and a 24-h GH secretion profile was compiled. Moreover, ionised Ca and insulin concentrations as well as mRNA and protein expression levels of hepatic proteins involved in GH signalling were quantified. Due to the protein-reduced diet, concentrations of ionised Ca, insulin and IGF1 decreased significantly, whereas GH concentrations remained unchanged. Expression levels of the hepatic GH receptor (GHR) decreased during protein reduction. GHR expression was down-regulated due to diminished insulin concentrations as both parameters were positively correlated. Insulin itself might be reduced due to reduced blood Ca levels that are involved in insulin release. The protein-reduced diet had an impact on the expression of components of the somatotropic axis as a disruption of the GH-IGF1 axis brought about by diminished GHR expression was shown in response to a protein-reduced diet.