The Adenosine Receptor Agonist 5’-N-Ethylcarboxamide-Adenosine Increases Mouse Serum Total Homocysteine Levels, Which Is a Risk Factor for Cardiovascular Diseases


An increase in total homocysteine (Hcy) levels (protein-bound and free Hcy in the serum) has been identified as a risk factor for vascular diseases. Hcy is a product of the methionine cycle and is a precursor of glutathione in the transsulfuration pathway. The methionine cycle mainly occurs in the liver, with Hcy being exported out of the liver and subsequently bound to serum proteins. When the non-specific adenosine receptor agonist 5’-N-ethylcarboxamide-adenosine (NECA; 0.1 or 0.3 mg/kg body weight) was intraperitoneally administered to mice that had been fasted for 16 h, total Hcy levels in the serum significantly increased 1 h after its administration. The NECA treatment may have inhibited transsulfuration because glutathione levels were significantly decreased in the liver. After the intraperitoneal administration of a high dose of NECA (0.3 mg/kg body weight), elevations in total Hcy levels in the serum continued for up to 10 h. The mRNA expression of methionine metabolic enzymes in the liver was significantly reduced 6 h after the administration of NECA. NECA-induced elevations in total serum Hcy levels may be maintained in the long term through the attenuated expression of methionine metabolic enzymes.

Share and Cite:

Sakata, S. , Matsuda, K. , Horikawa, Y. and Sasaki, Y. (2015) The Adenosine Receptor Agonist 5’-N-Ethylcarboxamide-Adenosine Increases Mouse Serum Total Homocysteine Levels, Which Is a Risk Factor for Cardiovascular Diseases. Pharmacology & Pharmacy, 6, 461-470. doi: 10.4236/pp.2015.610048.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] Antoniades, C., Antonopoulos, A.S., Tousoulis, D., Marinou, K. and Stefanadis, C. (2009) Homocysteine and Coronary Atherosclerosis: from Folate Fortification to the Recent Clinical Trials. European Heart Journal, 30, 6-15.
[2] Refsum, H., Ueland, P.M., Nygard, O. and Vollset, S.E. (1998) Homocysteine and Cardiovascular Disease. Annual Review of Medicine, 49, 31-62.
[3] Garcia-Tevijano, E.R., Berasain, C., Rodriguez, J.A., Corrales, F.J., Arias, R., Martin-Duce, A., Caballeria, J., Mato, J.M. and Avila, M.A. (2001) Hyperhomocysteinemia in Liver Cirrhosis: Mechanisms and Role in Vascular and Hepatic Fibrosis. Hypertension, 38, 1217-1221.
[4] Araki, A., Ito, H., Majima, Y., Hosoi, T. and Orimo, H. (2003) Association between Plasma Homocysteine Concentrations and Asymptomatic Cerebral Infarction or Leukoaraiosis in Elderly Diabetic Patients. Geriatrics & Gerontology International, 3, 15-23.
[5] Elanchezhian, R., Palsamy, P., Madson, C.J., Lynch, D.W. and Shinohara, T. (2012) Age-Related Cataracts: Homocysteine Coupled Endoplasmic Reticulum Stress and Suppression of Nrf2-Dependent Antioxidant Protection. Chemico-Biological Interactions, 200, 1-10.
[6] Mudd, S.H., Finkelstein, J.D., Refsum, H., Ueland, P.M., Malinow, M.R., Lentz, S.R., Jacobsen, D.W., Brattstrom, L., Wilcken, B., Wilcken, D.E., Blom, H.J., Stabler, S.P., Allen, R.H., Selhub, J. and Rosenberg, I.H. (2000) Homocysteine and Its Disulfide Derivatives: A Suggested Consensus Terminology. Arteriosclerosis Thrombosis and Vascular Biology, 20, 1704-1706.
[7] Finkelstein, J.D. (1990) Methionine Metabolism in Mammals. The Journal of Nutritional Biochemistry, 1, 228-237.
[8] Stipanuk, M.H. (2004) Sulfur Amino Acid Metabolism: Pathways for Production and Removal of Homocysteine and Cysteine. Annual Review of Nutrition, 24, 539-577.
[9] Chou, J.Y. (2000) Molecular Genetics of Hepatic Methionine Adenosyltransferase Deficiency. Pharmacology & Therapeutics, 85, 1-9.
[10] De La Haba, G. and Cantoni, G.L. (1959) The Enzymatic Synthesis of S-Adenosyl-L-Homocysteine from Adenosine and Homocysteine. The Journal of Biological Chemistry, 234, 603-608.
[11] Shintani, T., Iwabuchi, T., Soga, T., Kato, Y., Yamamoto, T., Takano, N., Hishiki, T., Ueno, Y., Ikeda, S., Sakuragawa, T., Ishikawa, K., Goda, N., Kitagawa, Y., Kajimura, M., Matsumoto, K. and Suematsu, M. (2009) Cystathionine Beta-Synthase as a Carbon Monoxide-Sensitive Regulator of Bile Excretion. Hepatology, 49, 141-150.
[12] Purohit, V., Abdelmalek, M.F., Barve, S., Benevenga, N.J., Halsted, C.H., Kaplowitz, N., Kharbanda, K.K., Liu, Q.Y., Lu, S.C., McClain, C.J., Swanson, C. and Zakhari, S. (2007) Role of S-Adenosylmethionine, Folate, and Betaine in the Treatment of Alcoholic Liver Disease: Summary of a Symposium. The American Journal of Clinical Nutrition, 86, 14-24.
[13] Mudd, S.H. and Poole, J.R. (1975) Labile Methyl Balances for Normal Humans on Various Dietary Regimens. Metabolism, 24, 721-735.
[14] Bontemps, F., Vincent, M.F. and Van den Berghe, G. (1993) Mechanisms of Elevation of Adenosine Levels in Anoxic Hepatocytes. Biochemical Journal, 290, 671-677.
[15] Fredholm, B.B. (2007) Adenosine, an Endogenous Distress Signal, Modulates Tissue Damage and Repair. Cell Death and Differentiation, 14, 1315-1323.
[16] Fredholm, B.B., Irenius, E., Kull, B. and Schulte, G. (2001) Comparison of The Potency of Adenosine as an Agonist at Human Adenosine Receptors Expressed in Chinese Hamster Ovary Cells. Biochemical Pharmacology, 61, 443-448.
[17] Fredholm, B.B., Ijzerman, A.P., Jacobson, K.A., Klotz, K.N. and Linden, J. (2001) International Union of Pharmacology. XXV. Nomenclature and Classification of Adenosine Receptors. Pharmacological Reviews, 53, 527-552.
[18] Ito, K., Miwa, N., Hagiwara, K., Yano, T., Shimizu-Saito, K., Goseki, N., Iwai, T. and Horikawa, S. (1999) Regulation of Methionine Adenosyltransferase Activity by the Glutathione Level in Rat Liver during Ischemia-Reperfusion. Surgery Today, 29, 1053-1058.
[19] Matsuda, K., Horikawa, Y., Sasaki, Y. and Sakata, S.F. (2014) The Adenosine Receptor Agonist 5’-N-Ethylcarboxamide-Adenosine Increases Glucose 6-Phosphatase Expression and Gluconeogenesis. Pharmacology & Pharmacy, 5, 15-23.
[20] Sakata, S.F., Fujino, M., Matsuda, K., Maeda, M., Ohira, H., Kawasaki, K. and Tamaki, N. (2007) Mechanism of Liver Tyrosine Aminotransferase Increase in Ethanol-Treated Mice and Its Effect on Serum Tyrosine Level. Journal of Nutritional Science & Vitaminology, 53, 489-495.
[21] Marston, H.M., Finlayson, K., Maemoto, T., Olverman, H.J., Akahane, A., Sharkey, J. and Butcher, S.P. (1998) Pharmacological Characterization of a Simple Behavioral Response Mediated Selectively by Central Adenosine A1 Receptors, Using in Vivo and in Vitro Techniques. Journal of Pharmacology and Experimental Therapeutics, 285, 1023-1030.
[22] Chomczynski, P. and Sacchi, N. (1987) Single-Step Method of RNA Isolation by Acid Guanidinium Thiocyanate-Phenol-Chloroform Extraction. Analytical Biochemistry, 162, 156-159.
[23] Sakata, S.F., Okumura, S., Matsuda, K., Horikawa, Y., Maeda, M., Kawasaki, K., Chou, J.Y. and Tamaki, N. (2005) Effect of Fasting on Methionine Adenosyltransferase Expression and the Methionine Cycle in the Mouse Liver. Journal of Nutritional Science & Vitaminology, 51, 118-123.
[24] Sakata, S.F., Tamaoka, K., Matsuda, K., Kaneko, M., Chou, J.Y. and Tamaki, N. (1998) Effect of Glucocorticoids on the Mouse Methionine Adenosyltransferase A1 Gene Expression, Which Is Regulated by Two Promoters. Biochimica et Biophysica Acta, 1442, 127-136.
[25] She, Q.B., Nagao, I., Hayakawa, T. and Tsuge, H. (1994) A Simple HPLC Method for the Determination of S-Adenosylmethionine and S-Adenosylhomocysteine in Rat Tissues: The Effect of Vitamin B6 Deficiency on These Concentrations in Rat Liver. Biochemical and Biophysical Research Communications, 205, 1748-1754.
[26] Baker, M.A., Cerniglia, G.J. and Zaman, A. (1990) Microtiter Plate Assay for the Measurement of Glutathione and Glutathione Disulfide in Large Numbers of Biological Samples. Analytical Biochemistry, 190, 360-365.
[27] Pfeiffer, C.M., Huff, D.L. and Gunter, E.W. (1999) Rapid and Accurate HPLC Assay for Plasma Total Homocysteine and Cysteine in a Clinical Laboratory Setting. Clinical Chemistry, 45, 290-292.
[28] Mato, J.M., Alvarez, L., Ortiz, P. and Pajares, M.A. (1997) S-Adenosylmethionine Synthesis: Molecular Mechanisms and Clinical Implications. Pharmacology & Therapeutics, 73, 265-280.
[29] Haschemi, A., Wagner, O., Marculescu, R., Wegiel, B., Robson, S.C., Gagliani, N., Gallo, D., Chen, J.F., Bach, F.H. and Otterbein, L.E. (2007) Cross-Regulation of Carbon Monoxide and The Adenosine A2a Receptor in Macrophages. The Journal of Immunology, 178, 5921-5929. jimmunol.178.9.5921
[30] del Pino, M.M., Corrales, F.J. and Mato, J.M. (2000) Hysteretic Behavior of Methionine Adenosyltransferase III. Methionine Switches between Two Conformations of the Enzyme with Different Specific Activity. The Journal of Biological Chemistry, 275, 23476-23482.
[31] Mitsui, K., Teraoka, H. and Tsukada, K. (1988) Complete Purification and Immunochemical Analysis of S-Adenosylmethionine Synthetase from Bovine Brain. The Journal of Biological Chemistry, 263, 11211-11216.
[32] Collinsova, M., Strakova, J., Jiracek, J. and Garrow, T.A. (2006) Inhibition of Betaine-Homocysteine S-Methyltransferase Causes Hyperhomocysteinemia in Mice. The Journal of Nutrition, 136, 1493-1497.
[33] Tanghe, K.A., Garrow, T.A. and Schalinske, K.L. (2004) Triiodothyronine Treatment Attenuates the Induction of Hepatic Glycine N-Methyltransferase by Retinoic Acid and Elevates Plasma Homocysteine Concentrations in Rats. The Journal of Nutrition, 134, 2913-2918.

Copyright © 2022 by authors and Scientific Research Publishing Inc.

Creative Commons License

This work and the related PDF file are licensed under a Creative Commons Attribution 4.0 International License.