Time-dependent changes of amino acids in the serum, liver, brain and urine of rats administered with theanine.
Abstract
Time-dependent changes of theanine (gamma-glutamylethylamide) and other amino acids in various tissues of rats were investigated during the 24 hrs after theanine administration. When theanine (4 g/kg of body weight) was intragastrically administered to rats, the concentrations of theanine in the serum, liver and brain were significantly increased 1 hr after its administration, and thereafter gradually decreased, but reached the maximum level in the brain after 5 hrs. Theanine in these tissues had completely disappeared 24 hrs after its administration. In contrast, the administration of theanine resulted in the concentrations of theanine, urea, ethylamine and glutamic acid in the urine being significantly enhanced. These results suggest that theanine might be degraded via glutamic acid.
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Integrity signals
Registry
Cites
Statistics
Claims the paper makes
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
In rats, oral or i.g. isolated L-theanine caused temporary increases in plasma, liver, brain, and urine, followed by higher plasma and urine ethylamine and glutamic acid, likely via hydrolysis.
“In rats, oral as well as i.g.administration of isolated L-theanine led to its temporary increase in plasma, liver, brain, and urine.This was followed by raised concentrations of ethylamine and glutamic acid in plasma and urine, probably due to hydrolysis of L-theanine (8,9).”
From Kinetics of ʟ-Theanine Uptake and Metabolism in Healthy Participants Are Comparable after Ingestion of ʟ-Theanine via Capsules and Green Tea4 (2012) · cites this paper as [9]
Materials and Methods (p. 1) describes intragastric administration, but not a separate oral-administration group. Results and Discussion (pp. 1–2) reports transient theanine increases in serum, liver and brain; urinary theanine instead continued to increase through 24 hours. The paper reports increased ethylamine and glutamic acid in urine and a tendency toward higher serum levels, and suggests degradation of theanine, but does not establish hydrolysis as the mechanism. (LLM, conf=0.88)
Experimental — accuracy not yet measuredBlood sampling times were selected because rat maximum plasma L-theanine occurred 0.5-1.0 h after administration and L-theanine remained detectable after 16 h.
“These intervals were chosen, because the maximum plasma concentration of L-theanine in rats occurred 0.5-1.0h after L-theanine administration (8,15) and L-theanine was still detectable after 16 h (8,9,15).”
From Kinetics of ʟ-Theanine Uptake and Metabolism in Healthy Participants Are Comparable after Ingestion of ʟ-Theanine via Capsules and Green Tea4 (2012) · cites this paper as [9]
The Results and Discussion (p. 1) report that rat serum theanine rose at 1 hour and then sharply decreased, supporting a peak around the measured 1-hour time point. The Methods (p. 1) show that 0.5 hours was not sampled, and the text does not explicitly establish that theanine remained detectable in serum at 16 hours; the reported detection through 24 hours concerns urine (Results and Discussion, p. 2). (LLM, conf=0.82)
Experimental — accuracy not yet measuredIn rats, L-theanine concentrations in liver and serum began to decrease after one hour, brain levels peaked at five hours then decreased, and total clearance occurred after 24 hours.
“In liver and serum, L-theanine concentrations started to decrease after 1 hour of its administration, whereas in the brain it peaked at 5 hours, when it started to decrease [67], and total clearance observed after 24 hours [67].”
From Psychotropic effects of L-theanine and its clinical properties: from the management of anxiety and stress to a potential use in schizophrenia (2019) · cites this paper as [67]
In rats, L-theanine was detected in neural tissue after intragastric administration and was transported via a leucine-preferring transport system.
“Also in rats, two separate studies from the same research group [60,67], detected the presence of L-theanine in neural tissue after its intragastric administration, and that this transport occurred via a leucinepreferring transport system.”
From Psychotropic effects of L-theanine and its clinical properties: from the management of anxiety and stress to a potential use in schizophrenia (2019) · cites this paper as [67]
Self-check
Percentages, sums and reported differences re-computed from the paper’s own numbers.
The self-check needs the paper’s full text.
Cites
Multiple Range and Multiple F Tests
Duncan, D. B. (1955) · Biometrics · doi:10.2307/3001478 · Cited by 23,446 · see citing works
Yokogoshi, H., Kobayashi, M., Mochizuki, M., & Terashima, T. (1998) · Neurochemical Research · doi:10.1023/a:1022490806093 · Cited by 229 · see citing works
Self-citationYokogoshi, H., Kato, Y., Sagesaka, Y. M., Takihara-Matsuura, T., Kakuda, T., & Takeuchi, N. (1995) · Bioscience, Biotechnology, and Biochemistry · doi:10.1271/bbb.59.615 · Cited by 192 · see citing works
Self-citationStudies on the Chemical Constituents of Tea
SAKATO, Y. (1950) · Journal of the agricultural chemical society of Japan · doi:10.1271/nogeikagaku1924.23.262 · Cited by 148 · see citing works
Theanine-induced reduction of brain serotonin concentration in rats
YOKOGOSHI, H., MOCHIZUKI, M., & SAITOH, K. (1998) · Bioscience, Biotechnology, and Biochemistry · doi:10.1271/bbb.62.816 · Cited by 83 · see citing works
Self-citationKitaoka, S., Hayashi, H., Yokogoshi, H., & Suzuki, Y. (1996) · Bioscience, Biotechnology, and Biochemistry · doi:10.1271/bbb.60.1768 · Cited by 63 · see citing works
Self-citationHypotensive effect of γ-glutamylmethylamide in spontaneously hypertensive rats
Yokogoshi, H., & Kobayashi, M. (1998) · Life Sciences · doi:10.1016/s0024-3205(98)00029-0 · Cited by 57 · see citing works
Self-citationOdagima, C. H., Kimura, Y., Adachi, S., et al. (1995) · Bioscience Biotechnology and Biochemistry · doi:10.1271/bbb.59.731 · Cited by 9 · see citing works
Flagged first, then by citations
Cited by
Sorted by citations
l-theanine reduces psychological and physiological stress responses
Kimura, K., Ozeki, M., Juneja, L. R., & Ohira, H. (2007) · Biological Psychology · doi:10.1016/j.biopsycho.2006.06.006 · Cited by 349 · see citing works
Hidese, S., Ogawa, S., Ota, M., Ishida, I., Yasukawa, Z., Ozeki, M., & Kunugi, H. (2019) · Nutrients · doi:10.3390/nu11102362 · Cited by 159 · see citing works
“Peripherally and centrally administered L-theanine has been reported to act on the brain [12,13], to modulate monoamine levels in the central nervous system [14–17], and glutamate and glycine neurotransmissions [18,19].”
BackgroundLu, K., Gray, M. A., Oliver, C., Liley, D. T., Harrison, B. J., Bartholomeusz, C. F., Phan, K. L., & Nathan, P. J. (2004) · Human Psychopharmacology: Clinical and Experimental · doi:10.1002/hup.611 · Cited by 139 · see citing works
Kelly, S. P., Gomez-Ramirez, M., Montesi, J. L., & Foxe, J. J. (2008) · The Journal of Nutrition · doi:10.1093/jn/138.8.1572s · Cited by 120 · see citing works
Yoto, A., Motoki, M., Murao, S., & Yokogoshi, H. (2012) · Journal of Physiological Anthropology · doi:10.1186/1880-6805-31-28 · Cited by 110 · see citing works
Self-citationSugiyama, T., & Sadzuka, Y. (2004) · Cancer Letters · doi:10.1016/j.canlet.2004.03.040 · Cited by 95 · see citing works
Lardner, A. L. (2014) · Nutritional Neuroscience · doi:10.1179/1476830513y.0000000079 · Cited by 92 · see citing works
Gomez-Ramirez, M., Kelly, S. P., Montesi, J. L., & Foxe, J. J. (2009) · Brain Topography · doi:10.1007/s10548-008-0068-z · Cited by 87 · see citing works
White, D., De Klerk, S., Woods, W., Gondalia, S., Noonan, C., & Scholey, A. (2016) · Nutrients · doi:10.3390/nu8010053 · Cited by 85 · see citing works
Liu, Q., Duan, H., Luan, J., Yagasaki, K., & Zhang, G. (2009) · Cytotechnology · doi:10.1007/s10616-009-9223-y · Cited by 83 · see citing works
Neuroprotective effect of γ-glutamylethylamide (theanine) on cerebral infarction in mice
Egashira, N., Hayakawa, K., Mishima, K., Kimura, H., Iwasaki, K., & Fujiwara, M. (2004) · Neuroscience Letters · doi:10.1016/j.neulet.2004.03.046 · Cited by 80 · see citing works
Williams, J., Sergi, D., McKune, A. J., Georgousopoulou, E. N., Mellor, D. D., & Naumovski, N. (2019) · Phytotherapy Research · doi:10.1002/ptr.6277 · Cited by 73 · see citing works
Yamada, T., Terashima, T., Okubo, T., Juneja, L. R., & Yokogoshi, H. (2005) · Nutritional Neuroscience · doi:10.1080/10284150500170799 · Cited by 72 · see citing works
Self-citationUnno, K., Fujitani, K., Takamori, N., Takabayashi, F., Maeda, K.-I., Miyazaki, H., Tanida, N., Iguchi, K., Shimoi, K., & Hoshino, M. (2011) · Free Radical Research · doi:10.3109/10715762.2011.566869 · Cited by 72 · see citing works
Unno, K., Tanida, N., Ishii, N., Yamamoto, H., Iguchi, K., Hoshino, M., Takeda, A., Ozawa, H., Ohkubo, T., Juneja, L. R., et al. (2013) · Pharmacology Biochemistry and Behavior · doi:10.1016/j.pbb.2013.09.004 · Cited by 72 · see citing works
Thangarajan, S., Deivasigamani, A., Natarajan, S. S., Krishnan, P., & Mohanan, S. K. (2014) · International Journal of Neuroscience · doi:10.3109/00207454.2013.872642 · Cited by 71 · see citing works
Yamada, T., Terashima, T., Kawano, S., Furuno, R., Okubo, T., Juneja, L. R., & Yokogoshi, H. (2009) · Amino Acids · doi:10.1007/s00726-007-0020-7 · Cited by 71 · see citing works
Self-citationScheid, L., Ellinger, S., Alteheld, B., Herholz, H., Ellinger, J., Henn, T., Helfrich, H.-P., & Stehle, P. (2012) · The Journal of Nutrition · doi:10.3945/jn.112.166371 · Cited by 70 · see citing works
Acute Effects of Theanine, Caffeine and Theanine–Caffeine Combination on Attention
Kahathuduwa, C. N., Dassanayake, T. L., Amarakoon, A. M. T., & Weerasinghe, V. S. (2017) · Nutritional Neuroscience · doi:10.1080/1028415x.2016.1144845 · Cited by 70 · see citing works
Effect of Green Tea Phytochemicals on Mood and Cognition
Dietz, C., & Dekker, M. (2017) · Current Pharmaceutical Design · doi:10.2174/1381612823666170105151800 · Cited by 70 · see citing works
Ingestion of theanine, an amino acid in tea, suppresses psychosocial stress in mice
Unno, K., Iguchi, K., Tanida, N., Fujitani, K., Takamori, N., Yamamoto, H., Ishii, N., Nagano, H., Nagashima, T., Hara, A., et al. (2013) · Experimental Physiology · doi:10.1113/expphysiol.2012.065532 · Cited by 69 · see citing works
Human disposition of L-theanine in tea or aqueous solution
van der Pijl, P. C., Chen, L., & Mulder, T. P. J. (2010) · Journal of Functional Foods · doi:10.1016/j.jff.2010.08.001 · Cited by 66 · see citing works
A 13-week dietary toxicity and toxicokinetic study with l-theanine in rats
Borzelleca, J. F., Peters, D., & Hall, W. (2006) · Food and Chemical Toxicology · doi:10.1016/j.fct.2006.03.014 · Cited by 63 · see citing works
ZHANG, G., MIURA, Y., & YAGASAKI, K. (2002) · Bioscience, Biotechnology, and Biochemistry · doi:10.1271/bbb.66.711 · Cited by 58 · see citing works
Protective effect of l-theanine on chronic restraint stress-induced cognitive impairments in mice
Tian, X., Sun, L., Gou, L., Ling, X., Feng, Y., Wang, L., Yin, X., & Liu, Y. (2013) · Brain Research · doi:10.1016/j.brainres.2013.01.048 · Cited by 57 · see citing works
Desai, M. J., & Armstrong, D. W. (2004) · Rapid Communications in Mass Spectrometry · doi:10.1002/rcm.1319 · Cited by 54 · see citing works
Effects of l-theanine on attention and reaction time response
Higashiyama, A., Htay, H. H., Ozeki, M., Juneja, L. R., & Kapoor, M. P. (2011) · Journal of Functional Foods · doi:10.1016/j.jff.2011.03.009 · Cited by 50 · see citing works
Lopes Sakamoto, F., Metzker Pereira Ribeiro, R., Amador Bueno, A., & Oliveira Santos, H. (2019) · Pharmacological Research · doi:10.1016/j.phrs.2019.104395 · Cited by 49 · see citing works
Pharmacokinetics of theanine enantiomers in rats.
Desai, M. J., Gill, M. S., Hsu, W. H., & Armstrong, D. W. (2005) · Chirality · doi:10.1002/chir.20144 · Cited by 47 · see citing works
Yamada, T., Terashima, T., Wada, K., Ueda, S., Ito, M., Okubo, T., Juneja, L. R., & Yokogoshi, H. (2007) · Life Sciences · doi:10.1016/j.lfs.2007.08.023 · Cited by 47 · see citing works
Self-citationMiyachi, T., Tsuchiya, T., Oyama, A., Tsuchiya, T., Abe, N., Sato, A., Chiba, Y., Kurihara, S., Shibakusa, T., & Mikami, T. (2013) · Journal of Parenteral and Enteral Nutrition · doi:10.1177/0148607112458798 · Cited by 40 · see citing works
L-theanine and immunity: a review
Chen, S., Kang, J., Zhu, H., Wang, K., Han, Z., Wang, L., Liu, J., Wu, Y., He, P., Tu, Y., et al. (2023) · Molecules · doi:10.3390/molecules28093846 · Cited by 44 · see citing works
Kahathuduwa, C. N., Dhanasekara, C. S., Chin, S.-H., Davis, T., Weerasinghe, V. S., Dassanayake, T. L., & Binks, M. (2018) · Nutrition Research · doi:10.1016/j.nutres.2017.11.002 · Cited by 40 · see citing works
Tamano, H., Fukura, K., Suzuki, M., Sakamoto, K., Yokogoshi, H., & Takeda, A. (2013) · Brain Research Bulletin · doi:10.1016/j.brainresbull.2013.02.005 · Cited by 33 · see citing works
Self-citationl-Theanine protects against excess dopamine-induced neurotoxicity in the presence of astrocytes
Takeshima, M., Miyazaki, I., Murakami, S., Kita, T., & Asanuma, M. (2016) · Journal of Clinical Biochemistry and Nutrition · doi:10.3164/jcbn.16-15 · Cited by 31 · see citing works
Takeda, A., Tamano, H., Suzuki, M., Sakamoto, K., Oku, N., & Yokogoshi, H. (2012) · Cellular and Molecular Neurobiology · doi:10.1007/s10571-011-9732-z · Cited by 25 · see citing works
Self-citationDashwood, R., & Visioli, F. (2025) · Nutrition Research · doi:10.1016/j.nutres.2024.12.008 · Cited by 22 · see citing works
Yilmaz, U., Buzdagli, Y., Polat, M. L., Bakir, Y., Ozhanci, B., Alkazan, S., & Ucar, H. (2023) · Journal of the International Society of Sports Nutrition · doi:10.1080/15502783.2023.2267536 · Cited by 19 · see citing works
Sadzuka, Y., Sugiyama, T., Nagamine, M., Umegaki, K., & Sonobe, T. (2006) · Food and Chemical Toxicology · doi:10.1016/j.fct.2005.07.010 · Cited by 10 · see citing works
EFSA Panel on Dietetic Products, N. A. A. (., Turck, D., Bresson, J., Burlingame, B., Dean, T., Fairweather‐Tait, S., Heinonen, M., Hirsch‐Ernst, K. I., Mangelsdorf, I., McArdle, H. J., et al. (2018) · EFSA Journal · doi:10.2903/j.efsa.2018.5266 · Cited by 7 · see citing works
FURUSHIMA, D., SUGIYAMA, I., NOMURA, Y., UNNO, K., & YAMADA, H. (2022) · Journal of Nutritional Science and Vitaminology · doi:10.3177/jnsv.68.540 · Cited by 4 · see citing works
Nathan, P. J., Lu, K., Gray, M., & Oliver, C. (2006) · Journal of Herbal Pharmacotherapy · doi:10.1080/j157v06n02_02
- Authors
- TERASHIMA, T., TAKIDO, J., & YOKOGOSHI, H.
- Affiliations
- Shizuoka University (JP)
- Venue
- Bioscience, Biotechnology, and Biochemistry
- Publisher
- Oxford University Press (OUP)
- Published
- 1999-01
- Volume
- 63
- Issue
- 4
- Pages
- 615-618
- ISSN
- 0916-8451 (ISSN-L)
- 1347-6947
- OpenAlex
- W2049167284
- Cited by
- 112
- References
- 8
- Citations by year
- 2026: 2 · 2025: 5 · 2024: 5 · 2023: 5 · 2022: 5 · 2021: 2 · 2020: 5 · 2019: 7 · 2018: 5 · 2017: 5 · 2016: 6 · 2015: 3 · 2014: 2 · 2013: 9 · 2012: 6
- FWCI
- 0.50
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Bioscience Biotechnology and Biochemistry (publishedVersion)
- PubMed (publishedVersion)
- Topics
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Biochemistry › Amino Acid Enzymes and Metabolism
- Life Sciences › Neuroscience › Biological Psychiatry › Tryptophan and brain disorders
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Biochemistry › Sulfur Compounds in Biology
- Keywords
- theanine, amino acid metabolism, tissue distribution, serum, liver, brain, urine, urea, ethylamine, glutamate, degradation pathways, rats
- MeSH terms
- Amino Acids, Animals, Brain Chemistry, Glutamates, Liver, Male, Time Factors, Rats, Wistar, Rats
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
Are you an author, or do you see a problem with this page? Request a review
