Figure 1. Effects of L-theanine on mRNA expression of amino acid transporters of (A) ASCT2, (B) EAAT3, (C) EAAT1, (D) CAT1, (E) B0AT1, (F) y+LAT1, and (G) 4F2hc in the duodenum of mice. CK (control), HLT (LTA—400 mg•kg−1•d−1), MLT (LTA—300 mg•kg−1•d−1), LLT (LTA—100 mg•kg−1•d−1), and LG (L-glutamine—300 mg•kg−1•d−1) groups. Values are presented as mean ± SD; n = 10/group. Different superscript letters in the same figure indicate statistically significant differences (p < 0.05).

Figure 1. Effects of L-theanine on mRNA expression of amino acid transporters of (A) ASCT2, (B) EAAT3, (C) EAAT1, (D) CAT1, (E) B0AT1, (F) y+LAT1, and (G) 4F2hc in the duodenum of mice. CK (control), HLT (LTA—400 mg•kg−1•d−1), MLT (LTA—300 mg•kg−1•d−1), LLT (LTA—100 mg•kg−1•d−1), and LG (L-glutamine—300 mg•kg−1•d−1) groups. Values are presented as mean ± SD; n = 10/group. Different superscript letters in the same figure indicate statistically significant differences (p < 0.05).

Figure 2. Effects of L-theanine on mRNA expression of amino acid transporters of (A) ASCT2, (B) EAAT3, (C) EAAT1, (D) CAT1, (E) B0AT1, (F) y+LAT1, and (G) 4F2hc in the jejunum of mice. CK (control), HLT (LTA—400 mg•kg−1•d−1), MLT (LTA—300 mg•kg−1•d−1), LLT (LTA—100 mg•kg−1•d−1), and LG (L-glutamine—300 mg•kg−1•d−1) groups. Values are presented as mean ± SD; n = 10/group. Different superscript letters in the same figure indicate statistically significant differences (p < 0.05).

Figure 2. Effects of L-theanine on mRNA expression of amino acid transporters of (A) ASCT2, (B) EAAT3, (C) EAAT1, (D) CAT1, (E) B0AT1, (F) y+LAT1, and (G) 4F2hc in the jejunum of mice. CK (control), HLT (LTA—400 mg•kg−1•d−1), MLT (LTA—300 mg•kg−1•d−1), LLT (LTA—100 mg•kg−1•d−1), and LG (L-glutamine—300 mg•kg−1•d−1) groups. Values are presented as mean ± SD; n = 10/group. Different superscript letters in the same figure indicate statistically significant differences (p < 0.05).

Figure 3. Effects of L-theanine on the protein expression of amino acid transporters of (A) ASCT2, (B) EAAT3, (C) EAAT1, (D) CAT1, (E) B0AT1, (F) y+LAT1, and (G) 4F2hc in the duodenum of mice. CK (control), HLT (LTA—400 mg•kg−1•d−1), MLT (LTA—300 mg•kg−1•d−1), LLT (LTA—100 mg•kg−1•d−1), and LG (L-glutamine—300 mg•kg−1•d−1) groups. Values are presented as mean ± SD; n = 3/group. Different superscript letters in the same figure indicate statistically significant differences (p < 0.05).

Figure 3. Effects of L-theanine on the protein expression of amino acid transporters of (A) ASCT2, (B) EAAT3, (C) EAAT1, (D) CAT1, (E) B0AT1, (F) y+LAT1, and (G) 4F2hc in the duodenum of mice. CK (control), HLT (LTA—400 mg•kg−1•d−1), MLT (LTA—300 mg•kg−1•d−1), LLT (LTA—100 mg•kg−1•d−1), and LG (L-glutamine—300 mg•kg−1•d−1) groups. Values are presented as mean ± SD; n = 3/group. Different superscript letters in the same figure indicate statistically significant differences (p < 0.05).

Figure 4. Effects of L-theanine on the protein expression of amino acid transporters of (A) ASCT2, (B) EAAT3, (C) EAAT1, (D) CAT1, (E) B0AT1, (F) y+LAT1, and (G) 4F2hc in the jejunum of mice. CK (control), HLT (LTA—400 mg•kg−1•d−1), MLT (LTA—300 mg•kg−1•d−1), LLT (LTA—100 mg•kg−1•d−1), and LG (L-glutamine—300 mg•kg−1•d−1) groups. Values are presented as mean ± SD; n = 3/group. Different superscript letters in the same figure indicate statistically significant differences (p < 0.05).

Figure 4. Effects of L-theanine on the protein expression of amino acid transporters of (A) ASCT2, (B) EAAT3, (C) EAAT1, (D) CAT1, (E) B0AT1, (F) y+LAT1, and (G) 4F2hc in the jejunum of mice. CK (control), HLT (LTA—400 mg•kg−1•d−1), MLT (LTA—300 mg•kg−1•d−1), LLT (LTA—100 mg•kg−1•d−1), and LG (L-glutamine—300 mg•kg−1•d−1) groups. Values are presented as mean ± SD; n = 3/group. Different superscript letters in the same figure indicate statistically significant differences (p < 0.05).

Figure 5. Effects of L-theanine on the phosphorylation status of proteins of mTOR, S6K1, and S6 in the jejunum (A–C) and duodenum (D–F) of mice. CK (control), HLT (LTA—400 mg•kg−1•d−1), MLT (LTA—300 mg•kg−1•d−1), LLT (LTA—100 mg•kg−1•d−1), and LG (L-glutamine—300 mg•kg−1•d−1) groups. Values are presented as mean ± SD; n = 3/group. Different superscript letters in the same figure indicate statistically significant differences (p < 0.05).

Figure 5. Effects of L-theanine on the phosphorylation status of proteins of mTOR, S6K1, and S6 in the jejunum (A–C) and duodenum (D–F) of mice. CK (control), HLT (LTA—400 mg•kg−1•d−1), MLT (LTA—300 mg•kg−1•d−1), LLT (LTA—100 mg•kg−1•d−1), and LG (L-glutamine—300 mg•kg−1•d−1) groups. Values are presented as mean ± SD; n = 3/group. Different superscript letters in the same figure indicate statistically significant differences (p < 0.05).

Table 1. Effects of L-theanine on serum biochemical indexes in mice. CK (control), HLT (LTA—400 mg•kg−1•d−1), MLT (LTA—300 mg•kg−1•d−1), LLT (LTA—100 mg•kg−1•d−1), and LG (L-glutamine—300 mg•kg−1•d−1) groups. Different superscript letters in the same table indicate statistically significant differences.

Table 1. Effects of L-theanine on serum biochemical indexes in mice. CK (control), HLT (LTA—400 mg•kg−1•d−1), MLT (LTA—300 mg•kg−1•d−1), LLT (LTA—100 mg•kg−1•d−1), and LG (L-glutamine—300 mg•kg−1•d−1) groups. Different superscript letters in the same table indicate statistically significant differences.

CKLGLLTMLTHLTTP/(g/L)56.69 ± 11.29 a71.37 ± 19.39 b54.34 ± 8.54 ab59.49 ± 17.21 ab76.98 ± 18.26 bTG/(mmol/L)1.39 ± 0.44 ab1. 86 ± 0.61 c1.06 ± 0.31 a1.34 ± 0.21 ab1.74 ± 0.69 bcAST/(U/L)101.24 ± 18.98106.23 ± 11.84110.2 ± 24.56100.41 ± 35.56110.21 ± 26.31ALT/(U/L)34.17 ± 2.9835.99 ± 5.7435.28 ± 5.4237.89 ± 6.0136.25 ± 6.33LDL-C/(mmol/L)1.62 ± 0.811.57 ± 0.631.51 ± 0.481.66 ± 0.711.59 ± 0.84Alb/(g/L)38.59 ± 3.4640.09 ± 8.3335.39 ± 5.0842.33 ± 8.2141.84 ± 9.34BUN/(mmol/L)7.62 ± 0.54 b6.79 ± 0.59 a7.12 ± 0.26 b7.02 ± 0.21 a7.47 ± 0.26 aGlucose/(mmol/L)4.39 ± 0.815.12 ± 1.824.55 ± 1.265.39 ± 0.954.96 ± 1.38T-CHO/(mmol/L)4.33 ± 0.814.32 ± 0.584.06 ± 0.584.87 ± 0.394.22 ± 0.79HDL-C/(mmol/L)2.04 ± 0.292.39 ± 0.341.77 ± 0.242.06 ± 0.742.1 ± 0.63AKP/(U/L)158.51 ± 24.98 a171.58 ± 16.68 b137.28 ± 11.25 a151.34 ± 12.39 a161.24 ± 24.33 b

Table 2. Effects of L-theanine on amino acid content in mouse duodenum. CK (control), HLT (LTA—400 mg•kg−1•d−1), MLT (LTA—300 mg•kg−1•d−1), LLT (LTA—100 mg•kg−1•d−1), and LG (L-glutamine—300 mg•kg−1•d−1) groups. Different superscript letters in the same table indicate statistically significant differences

Table 2. Effects of L-theanine on amino acid content in mouse duodenum. CK (control), HLT (LTA—400 mg•kg−1•d−1), MLT (LTA—300 mg•kg−1•d−1), LLT (LTA—100 mg•kg−1•d−1), and LG (L-glutamine—300 mg•kg−1•d−1) groups. Different superscript letters in the same table indicate statistically significant differences

CKLGLLTMLTHLTTransporterOrn159.97 ± 23.14 a362.35 ±25.85 c276 ± 22.36 b255.84 ± 23.28 b256.32 ± 15.32 bCAT1Arg1458.78 ± 158.89 a2175.23 ±76.39 c1489.36 ± 124.27 a1839.42 ± 310.22 b2043.5 ± 168.58 bcCAT1, 4F2hc+y+LAT1Lys1192.08 ± 198.74 a2038.21 ± 144.43 d1570.75 ±126.37 b1748.23 ±188.96 c1885.23 ± 126.66 cdCAT1, 4F2hc+y+LAT1His240.13 ± 24.36 a341.25 ± 23.79 bc332.26 ± 17.32 b358.28 ± 15.32 bc355.56 ±16.2 cCAT1, 4F2hc+y+LAT1Gly651.14 ± 15.87 a746.36 ± 28.97 b842.89 ± 34.82 c903.25 ± 34.45 d855.23 ± 56.32 cB0AT1Ile683.31 ± 43.28 a1004.3 ±58.89 b921.57 ± 48.59 b1005.37 ± 44.45 b1084.23 ± 48.96 cB0AT1Val632.79 ± 58.23 a894.28 ± 98.74 bc826.52 ± 83.59 b966.2 ± 87.32 bc967.78 ± 98.56 cB0AT1Phe913.17 ± 88.23 a1527.18 ± 148.58 c1189.37 ± 86.59 b1244.59 ± 245.6 bc1396 ± 133.58 cB0AT1Tyr873.56 ± 94.31 a1501.2 ± 103.25 c1221.35 ± 122.32 b1127 ± 213.31 bc1298.98 ± 188.65 cB0AT1Trp264.85 ± 23.37 a415.01 ± 43.23 cd322.58 ± 34.32 b401.12 ± 48.86 bc387.86 ± 43.23 cB0AT1Pro473.85 ± 76.36 a573.18 ± 96.26 ab538.28 ± 43.54 a711.9 ± 97.23 c654.59 ± 84.23 bcB0AT1Asp769.48 ± 39.28 a845.58 ± 23.36 ab911.23 ± 41.25 b1211.23 ± 56.59 c943.82 ± 58.64 bEAAT1, EAAT3Glu1628.12 ± 141.28 a1889 ± 58.72 b1844.28 ± 87.27 b2335.2 ± 156.36 c2021.32 ± 144.23 bEAAT1, EAAT3Ala1003.25 ± 48.69 a1012.29 ± 56.34 c1186.58 ± 46.69 b1354.23 ± 54.39 d1417.68 ± 18.37 dASCT2, B0AT1Ser799.31 ± 36.52 a965.33 ± 28.34 b1000.23 ± 33.28 b1133.57 ± 134.34 c1078.23 ± 62.58 cASCT2, B0AT1Cys14.88 ± 2.02 a21.15 ± 2.18 c18.23 ± 1.3 b21.64 ± 2.37 c22.89 ± 5.35 cASCT2, B0AT1Thr591.48 ± 54.28 a803.26 ± 69.56 bc784.56 ± 72.23 b831.26 ± 58.88 c852.69 ± 48.83 cASCT2, B0AT1Met229.14 ± 20.37 a358 ± 28.35 c288.37 ± 35.28 b343.27 ± 48.29 bc348.33 ± 33.23 c4F2hc+y+LAT1, B0AT1Leu1382.85 ± 93.21 a2315.28 ± 232.28 c2002.31 ± 245.58 b2012.67 ± 94.73 b2338 ± 83.26 c4F2hc+y+LAT1, B0AT1

Table 3. Effects of L-theanine on amino acid content in mouse jejunum. CK (control), HLT (LTA—400 mg•kg−1•d−1), MLT (LTA—300 mg•kg−1•d−1), LLT (LTA—100 mg•kg−1•d−1), and LG (L-glutamine—300 mg•kg−1•d−1) groups. Different superscript letters in the same table indicate statistically significant differences

Table 3. Effects of L-theanine on amino acid content in mouse jejunum. CK (control), HLT (LTA—400 mg•kg−1•d−1), MLT (LTA—300 mg•kg−1•d−1), LLT (LTA—100 mg•kg−1•d−1), and LG (L-glutamine—300 mg•kg−1•d−1) groups. Different superscript letters in the same table indicate statistically significant differences

CKLGLLTMLTHLTTransporterOrn107.31 ± 8.01 a131.24 ± 12.1 b135.3 ± 21.09 b171.85 ± 21.33 c213.25 ± 42.32 dCAT1Arg1389.69 ± 184.43 a1784.38 ± 201.32 b1398.21 ± 84.67 a2258.33 ± 142.25 c2731.78 ± 200.8 dCAT1, 4F2hc+y+LAT1Lys1000.74 ± 135.32 a1321.54 ± 142.32 b1352.3 ± 162.36 b1821.5 ± 274.36 c2001.46 ± 312.25 dCAT1, 4F2hc+y+LAT1His274.32 ± 30.26 a371.16 ± 31.28 b263.54 ± 23.14 a374.18 ± 51.39 b513.45 ± 105.11 cCAT1, 4F2hc+y+LAT1Gly1471.41 ± 103.54 a1698.87 ± 103.9 a1691.34 ± 203.1 a2256.64 ± 266.32 b2301.32 ± 288.87 bB0AT1Ile864.59 ± 144.36 a1031.48 ± 85.38 b1024.43 ± 214.36 b1632.12 ± 103.74 c1701.25 ± 587.32 cB0AT1Val846.34 ± 113.58 a1058.64 ± 148.32 b1034.25 ± 132.71 ab15385.37 ± 233.41 c1721.82 ± 186.54 dB0AT1Phe1161.47 ± 153.73 a1284.3 ± 201.31 a1187.6 ± 177.36 a1864.64 ± 135.37 b2121.53 ± 155.31 cB0AT1Tyr1196.54 ± 105.41 a1498.29 ± 102.3 b1289.54 ± 86.52 a2013.54 ± 143.54 c2418.31 ± 112.35 dB0AT1Trp322.3 ± 53.2 a379.27 ± 52.54 b339.73 ± 27.64 ab499.28 ± 29.34 c562.27 ± 56.38 cB0AT1Pro341.58 ± 27.61 a446.29 ± 56.35 b584.6 ± 69.45 c801.38 ± 84.65 d881.83 ± 74.39 dB0AT1Asp1337 ± 172.47 a1293.4 ± 112.3 a1487.25 ± 201.36 a1881.26 ± 136.97 b1843.21 ± 111.36 bEAAT1, EAAT3Glu3986.3 ± 397.84 a4026.76 ±503.29 a4258.31 ±871.24 ab5084.63 ±614.85 b5023.65 ± 540.32 bEAAT1, EAAT3Ala2010.48 ± 121.59 a2085.64 ± 103.2 a2489.66 ± 187.36 b2917.35 ± 147.23 c3128.25 ± 188.98 cASCT2, B0AT1Ser1001.54 ± 82.38 a1336.57 ± 142.05 b1022.59 ± 124.31 a1501 ± 142.32 c1854.58 ± 155.32 dASCT2, B0AT1Cys25.84 ± 1.89 a30.28 ± 2.56 b28.56 ± 2.33 ab31.08 ± 3.56 b30.02 ± 3.21 bASCT2, B0AT1Thr784.25 ± 74.66 a978.24 ± 143.69 b996.27 ± 100.2 b1321.28 ± 91.23 c1563.21 ± 108.28 dASCT2, B0AT1Met271.69 ± 26.31 a361.32 ± 62.38 b321.83 ± 41.85 ab459.26 ± 71.23 c504.1 ± 58.23 c4F2hc+y+LAT1, B0AT1Leu1842.36 ± 351.87 a2018.37 ± 312.56 a2063.89 ± 141.54 a3233.16 ± 399.98 b3269.58 ± 532.34 b4F2hc+y+LAT1, B0AT1