In C57BL mice, a tracer amount of methionine (Met) at a concentration approximate to that in the blood was administered in the tail vein (i.V.). The rates of endogenous metabolic decomposition of methionine were obtained by using three specifically labelled compounds, [l-14C]-Met, [m-14C]-Met and [35S]-Met Results on the kinetics and dynamics after i.v. administration suggested that S min after administration, most of the labelled compounds were taken up into the organs and tissues, and only a small portion was excreted in the expired air as CO2, the final metabolite of methionine. At 30 min the radioactive concentration in blood was minimal and was consistent with the maximum of the14CO2 excretion in expired air. Gradual increase of the radioactive concentration in blood after 30 min might be due to the contribution of the metabolite in the blood. Methionine taken up was endogenously utilized by more than 40% during 48 h and it maintained the order of [1-14C] : [m-14C] : [35S].
Out of the remaining 60%, 40% was metabolized in 6 h after administration, the [1-14C] moiety being excreted mainly into expired air, the [m-14C] moiety into expired air and urine, and the [35S] moiety mainly into urine and partly into faeces.
Microautoradiograms revealed that a part of the last 20% was taken up into the enzyme proteins contained in the pancreatic juice and intestinal juice, and was decomposed within 48 h.
This is a preview of subscription content, log in to check access.
Buy single article
Instant access to the full article PDF.
Price includes VAT for USA
Placidi G.F., Fomaro P., Guarneri M., Stramentionoli G. (1979): Localization of S-[methyl-14C] adenosyl-L-methionine in pregnant mice and fetuses as determined by autoradiography. Eur. J. Drug Metab. Phamacokinet, 4, 157–161.
Friedberg F., Tarver H., Greenberg D.M. (1948): The distribution pattern of sulfur labelled methionines in the protein and the free amino acid fraction of tissues after intravenous administration. J. Biol. Chem, 173, 344–361.
Chen S., Zieve L., Mahadevan V. (1970): Mercaptans and dimethyl sulfide in the breath of patients with cirrhosis of the liver. J. Lab. Clin. Med, 75, 628–635.
Momose Y., Shigematsu A. (1989): Radiospirometric patterns of14C-substrates in rats I. Differences in kind of14-substrates and their structural positions labelled with14C. Eur. J. Drug Metab. Pharmacokinet, 14, 187–194.
Kojima M., Murayama D., Shigematsu A. (1967): A new microautoradiography for hydrophylic and lipophilic compounds labelled with soft emitter. Radioisotopes, 16, 161–166.
Mabuchi Y., Nakazawa T., Momose Y., Motoji N., Hayama E., Hatori A. (1986): Xenobio. Metabol. Disp, 1, 306–307.
About this article
Cite this article
Hayama, E., Motoji, N. & Shigematsu, A. The kinetics and dynamics of three kinds of radioactive methionine after i.v. administration in mice. European Journal of Drug Metabolism and Pharmacokinetics 16, 287–297 (1991). https://doi.org/10.1007/BF03189974