Radioimmunoassay for 5-methyltetrahydrohomofolate
A radioimmunoassay for 5-methyltetrahydrohomofolate has been developed by using antibody induced in rabbits by 5-methyltetrahydrohomofolate-bovine serum albumin conjugates. The labeled drug was prepared by condensing it with (/sub 3/H)histamine or (/sub 125/I)histamine. The assay employing either isotope was simple and reproducible and had identical sensitivities. The specificity of the antibody was characterized by comparing the effectiveness of various related compounds in displacing labeled 5-methyltetrahydrohomofolate from the binding site of the antisera. At concentrations up to 1000 microgram/ml, homofolate acid, tetrahydrohomofolic acid, folic acid and methotrexate showed no competition for the binding. 5-methyltetrahydrofolic acid and 5-formyltetrahydrofolic acid cross-reacted with the antisera; the concentrations producing 50% binding inhibition were 2.8 and 24 microgram, respectively, as compared to 0.01 microgram for 5-methyltetrahydrohomofolate. The assay can be used for measuring the drug in plasma and tissues. This study supports its usability for clinical pharmacologic studies.
- OSTI ID:
- 5392991
- Journal Information:
- J. Pharmacol. Exp. Ther.; (United States), Vol. 218:2
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
DRUGS
RADIOIMMUNOASSAY
IODINE 125
ISOTOPE APPLICATIONS
TRITIUM COMPOUNDS
ANTIBODIES
FOLIC ACID
HISTAMINE
IMMUNE SERUMS
METABOLITES
PHARMACOLOGY
PRECURSOR
AMINES
AMINO ACIDS
AZOLES
BETA DECAY RADIOISOTOPES
CARBOXYLIC ACIDS
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
HEMATINICS
HEMATOLOGIC AGENTS
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
IMIDAZOLES
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPES
LABELLED COMPOUNDS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PTERIDINES
RADIOASSAY
RADIOISOTOPES
TRACER TECHNIQUES
VITAMIN B GROUP
VITAMINS
550601* - Medicine- Unsealed Radionuclides in Diagnostics
550201 - Biochemistry- Tracer Techniques