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Leucine regulates α-amylase and trypsin synthesis in dairy calf pancreatic tissue in vitro via the mammalian target of rapamycin signalling pathway

  • L. Guo (a1), J. H. Yao (a1), C. Zheng (a1), H. B. Tian (a1), Y. L. Liu (a1), S. M. Liu (a2), C. J. Cai (a1), X. R. Xu (a1) and Y. C. Cao (a1)...


Starch digestion in the small intestines of the dairy cow is low, to a large extent, due to a shortage of syntheses of α-amylase. One strategy to improve the situation is to enhance the synthesis of α-amylase. The mammalian target of rapamycin (mTOR) signalling pathway, which acts as a central regulator of protein synthesis, can be activated by leucine. Our objectives were to investigate the effects of leucine on the mTOR signalling pathway and to define the associations between these signalling activities and the synthesis of pancreatic enzymes using an in vitro model of cultured Holstein dairy calf pancreatic tissue. The pancreatic tissue was incubated in culture medium containing l-leucine for 3 h, and samples were collected hourly, with the control being included but not containing l-leucine. The leucine supplementation increased α-amylase and trypsin activities and the messenger RNA expression of their coding genes (P <0.05), and it enhanced the mTOR synthesis and the phosphorylation of mTOR, ribosomal protein S6 kinase 1 and eukaryotic initiation factor 4E-binding protein 1 (P <0.05). In addition, rapamycin inhibited the mTOR signal pathway factors during leucine treatment. In sum, the leucine regulates α-amylase and trypsin synthesis in dairy calves through the regulation of the mTOR signal pathways.


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Anonymous 1976. Adaptive responses of amino acid degrading enzymes to variation of amino acid and protein intake. Nutrition Reviews 34, 343345.
Appuhamy, JA, Knoebel, NA, Nayananjalie, WA, Escobar, J and Hanigan, MD 2012. Isoleucine and leucine independently regulate mTOR signaling and protein synthesis in MAC-T cells and bovine mammary tissue slices. Journal of Nutrition 142, 484491.
Arriola Apelo, SI, Singer, LM, Lin, XY, McGilliard, ML, St-Pierre, NR and Hanigan, MD 2014. Isoleucine, leucine, methionine, and threonine effects on mammalian target of rapamycin signaling in mammary tissue. Journal of Dairy Science 97, 10471056.
Averous, J, Lambert-Langlais, S, Carraro, V, Gourbeyre, O, Parry, L, B’Chir, W, Muranishi, Y, Jousse, C, Bruhat, A, Maurin, AC, Proud, CG and Fafournoux, P 2014. Requirement for lysosomal localization of mTOR for its activation differs between leucine and other amino acids. Cell Signal 26, 19181927.
Brannon, PM 1990. Adaptation of the exocrine pancreas to diet. Annual Review of Nutrition 10, 85105.
Budanov, A and Karin, M 2008. p53 target genes sestrin1 and sestrin2 connect genotoxic stress and mTOR signaling. Cell 134, 451460.
Byfield, MP, Murray, JT and Backer, JM 2005. hVps34 is a nutrient-regulated lipid kinase required for activation of p70 S6 kinase. Journal of Biological Chemistry 280, 3307633082.
Cao, YC, Yang, XJ, Guo, L, Zheng, C, Wang, DD, Cai, CJ, Liu, SM and Yao, JH 2018. Effects of dietary leucine and phenylalanine on pancreas development, enzyme activity, and relative gene expression in milk-fed Holstein dairy calves. Journal Dairy Science 101, 110.
Guba, M, von Breitenbuch, P, Steinbauer, M, Koehl, G, Flegel, S, Hornung, M, Bruns, CJ, Zuelke, C, Farkas, S, Anthuber, M, Jauch, KW and Geissler, EK 2002. Rapamycin inhibits primary and metastatic tumor growth by antiangiogenesis: involvement of vascular endothelial growth factor. Nature Medicine 8, 128.
Guo, L, Liang, ZQ, Zheng, C, Liu, BL, Yin, QY, Cao, YC and Yao, JH 2018. Leucine affects amylase synthesis through PI3K/Akt-mTOR signaling pathways in pancreatic acinar cells of dairy calves. Journal of Agricultural and Food Chemistry 66, 51495156.
Harmon, DL 1992. Dietary influences on carbohydrases and small intestinal starch hydrolysis capacity in ruminants. Journal of Nutrition 122, 203210.
Harper, AE, Benton, DA and Elvehjem, CA 1955. l-Leucine, an isoleucine antagonist in the rat. Archives of Biochemistry and Biophysics 57, 112.
Holz, MK, Ballif, BA, Gygi, SP and Blenis, J 2005. mTOR and S6K1 mediate assembly of the translation preinitiation complex through dynamic protein interchange and ordered phosphorylation events. Cell 123, 569580.
Huntington, GB, Harmon, DL and Richards, CJ 2006. Sites, rates, and limits of starch digestion and glucose metabolism in growing cattle. Journal of Animal Science 84, E1424.
Jiang, W, Zhu, Z and Thompson, HJ 2008. Dietary energy restriction modulates the activity of AMPK, Akt, and mTOR in mammary carcinomas, mammary gland, and liver. Cancer Research 68, 54925499.
Ju, HG and Chang, KK 2015. Effects of different doses of leucine ingestion following eight weeks of resistance exercise on protein synthesis and hypertrophy of skeletal muscle in rats. Journal of Exercise Nutrition & Biochemistry 19, 3138.
Katoh, K and Tsuda, T 1984. Effects of acetylcholine and shortchain fatty acids on acinar cells of the exocrine pancreas in sheep. Journal of Physiology 356, 479489.
Katoh, K and Yajima, T 1989. Effects of butyric acid and analogues on amylase release from pancreatic segments of sheep and goats. Pflugers Archiv-European Journal of Physiology 413, 256260.
Kimball, SR and Jefferson, LS 2004. Regulation of global and specific mRNA translation by oral administration of branched-chain amino acids. Biochemical and Biophysical Research Communications 313, 423427.
Kimball, SR and Jefferson, LS 2006. New functions for amino acid: effects on gene transcription and translation. American Journal of Clinical Nutrition 83, 500507.
Lang, CH, Frost, RA, Deshpande, N, Kumar, V, Vary, TC, Jefferson, LS and Kimball, SR 2003. Alcohol impairs leucine-mediated phosphorylation of 4E-BP1, S6K1, eIF4G, and mTOR in skeletal muscle. American Journal of Physiology-Endocrinology and Metabolism 285, 12051215.
Layman, DK and Walker, DA 2006. Potential importance of leucine in treatment of obesity and the metabolic syndrome. Journal of Nutrition 136, 319323.
Liu, K, Liu, Y, Liu, SM, Xu, M, Yu, ZP, Wang, X, Cao, YC and Yao, JH 2015. Relationships between leucine and the pancreatic exocrine function for improving starch digestibility in ruminants. Journal of Dairy Science 98, 25762582.
Mackle, TR, Dwyer, DA, Ingvartsen, KL, Chouinard, PY, Ross, DA and Bauman, DE 2000. Effects of insulin and postruminal supply of protein on use of amino acids by the mammary gland for milk protein synthesis. Journal of Dairy Science 83, 93105.
Meyuhas, O 2000. Synthesis of the translational apparatus is regulated at the translational level. European Journal of Biochemistry 267, 63216330.
Owens, FN, Zinn, RA and Kim, YK 1986. Limits to starch digestion in the ruminant small intestine. Journal of Animal Science 63, 16341648.
Phung, TL, Ziv, K, Dabydeen, D, Eyiah-Mensah, G, Riveros, M, Perruzzi, C, Sun, J, Monahan-Earley, RA, Shiojima, I, Nagy, JA, Lin, MI, Walsh, K, Dvorak, AM, Briscoe, DM, Neeman, M, Sessa, WC, Dvorak, HF and Benjamin, LE 2006. Pathological angiogenesis is induced by sustained Akt signaling and inhibited by rapamycin. Cancer Cell 10, 159170.
Raman, N, Nayak, A and Muller, S 2014. mTOR signaling regulates nucleolar targeting of the SUMO-specific isopeptidase SENP3. Molecular & Cellular Biology 34, 44744484.
Richards, CJ, Branco, AF, Bohnert, DW, Huntington, GB, Macari, M and Harmon, DL 2002. Intestinal starch disappearance increased in steers abomasally infused with starch and protein. Journal of Animal Science 80, 33613368.
Soulard, A and Hall, MN 2007. SnapShot: mTOR signaling. Cell 129, 434.
Sugawara, T, Ito, Y, Nishizawa, N and Nagasawa, T 2009. Regulation of muscle protein degradation, not synthesis, by dietary leucine in rats fed a protein-deficient diet. Amino Acids 37, 609616.
Swanson, KC, Matthews, JC, Matthews, AD, Howell, JA, Richards, CJ and Harmon, DL 2000. Dietary carbohydrate source and energy intake influence the expression of pancreatic alpha-amylase in lambs. Journal of Nutrition 130, 21572165.
Swanson, KC, Matthews, JC, Woods, CA and Harmon, DL 2002. Influence of substrate and/or neurohormonal mimic on in vitro pancreatic enzyme release from calves’ postruminally infused with partially hydrolyzed starch and/or casein. Journal of Animal Science 81, 13231331.
Wang, X and Proud, CG. 2006. The mTOR pathway in the control of protein synthesis. Physiology 21, 362369.
Wolfson, RL, Chantranupong, L, Saxton, RA, Shen, K, Scaria, SM, Cantor, JR and Sabatini, DM 2016. Sestrin2 is a leucine sensor for the mTORC1 pathway. Science 351, 4348.
Wu, G 2013. Functional amino acids in nutrition and health. Amino Acids 45, 407411.
Wu, G. 2014. Amino acid nutrition in animals: protein synthesis and beyond. Annual Review of Animal Bioscience 2, 387.
Yu, ZP, Xu, M, Liu, K, Yao, JH, Yu, HX and Wang, F. 2014. Leucine markedly regulates pancreatic exocrine secretion in goats. Journal of Animal Physiology and Animal Nutrition 98, 169177.


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