{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,18]],"date-time":"2026-05-18T22:22:19Z","timestamp":1779142939583,"version":"3.51.4"},"reference-count":49,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2022,12,28]],"date-time":"2022-12-28T00:00:00Z","timestamp":1672185600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"The National Natural Science Foundation of China","award":["31871804"],"award-info":[{"award-number":["31871804"]}]},{"name":"The National Natural Science Foundation of China","award":["2020JJ4036"],"award-info":[{"award-number":["2020JJ4036"]}]},{"name":"Natural Science Foundation Project of Hunan Province, China","award":["31871804"],"award-info":[{"award-number":["31871804"]}]},{"name":"Natural Science Foundation Project of Hunan Province, China","award":["2020JJ4036"],"award-info":[{"award-number":["2020JJ4036"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Nutrients"],"abstract":"<jats:p>The intestine is a key organ for the absorption of amino acids. L-theanine (LTA) is a structural analog of glutamine and a characteristic non-protein amino acid found in tea (Camellia sinensis) that regulates lipid and protein metabolism. The present study explored the role of LTA in intestinal amino acid absorption, protein synthesis, and its mechanisms. Overall, our findings suggest that LTA supplementation not only affects serum alkaline phosphatase (AKP), total protein (TP), and urea nitrogen (BUN) levels, but it also upregulates the mRNA and protein expression of amino acid transporters (EAAT3, EAAT1, 4F2hc, y+LAT1, CAT1, ASCT2, and B0AT1), and activates the mTOR signaling pathway. The downstream S6 and S6K1 proteins are regulated, and the expression of amino acid transporters is regulated. These findings suggest that LTA increases intestinal AA absorption, promotes protein metabolism, and increases nitrogen utilization by upregulating AAT expression, activating the mTOR signaling pathway, and phosphorylating the mTOR downstream proteins S6 and S6K1.<\/jats:p>","DOI":"10.3390\/nu15010142","type":"journal-article","created":{"date-parts":[[2022,12,28]],"date-time":"2022-12-28T05:30:27Z","timestamp":1672205427000},"page":"142","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":16,"title":["L-Theanine Regulates the Abundance of Amino Acid Transporters in Mice Duodenum and Jejunum via the mTOR Signaling Pathway"],"prefix":"10.3390","volume":"15","author":[{"given":"Kehong","family":"Liu","sequence":"first","affiliation":[{"name":"Key Lab of Tea Science of Ministry of Education, Hunan Agricultural University, Changsha 410128, China"},{"name":"National Research Center of Engineering Technology for Utilization of Botanical Functional Ingredients, Hunan Agricultural University, Changsha 410128, China"},{"name":"Co-Innovation Center of Education Ministry for Utilization of Botanical Functional Ingredients, Changsha 410128, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yingqi","family":"Peng","sequence":"additional","affiliation":[{"name":"Key Lab of Tea Science of Ministry of Education, Hunan Agricultural University, Changsha 410128, China"},{"name":"National Research Center of Engineering Technology for Utilization of Botanical Functional Ingredients, Hunan Agricultural University, Changsha 410128, China"},{"name":"Guangdong Agricultural Technology Extension Center, Guangzhou 510520, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ling","family":"Lin","sequence":"additional","affiliation":[{"name":"Key Lab of Tea Science of Ministry of Education, Hunan Agricultural University, Changsha 410128, China"},{"name":"National Research Center of Engineering Technology for Utilization of Botanical Functional Ingredients, Hunan Agricultural University, Changsha 410128, China"},{"name":"Co-Innovation Center of Education Ministry for Utilization of Botanical Functional Ingredients, Changsha 410128, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Zhihua","family":"Gong","sequence":"additional","affiliation":[{"name":"Key Lab of Tea Science of Ministry of Education, Hunan Agricultural University, Changsha 410128, China"},{"name":"National Research Center of Engineering Technology for Utilization of Botanical Functional Ingredients, Hunan Agricultural University, Changsha 410128, China"},{"name":"Co-Innovation Center of Education Ministry for Utilization of Botanical Functional Ingredients, Changsha 410128, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6258-4414","authenticated-orcid":false,"given":"Wenjun","family":"Xiao","sequence":"additional","affiliation":[{"name":"National Research Center of Engineering Technology for Utilization of Botanical Functional Ingredients, Hunan Agricultural University, Changsha 410128, China"},{"name":"Co-Innovation Center of Education Ministry for Utilization of Botanical Functional Ingredients, Changsha 410128, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yinhua","family":"Li","sequence":"additional","affiliation":[{"name":"Key Lab of Tea Science of Ministry of Education, Hunan Agricultural University, Changsha 410128, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,12,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1119","DOI":"10.1007\/s00217-020-03470-7","article-title":"New insights into the alterations of full spectrum amino acids in human colostrum and mature milk between different domains based on metabolomics","volume":"246","author":"Li","year":"2020","journal-title":"Eur. 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