Biomaterial Database

Radioenzymatic determination of phenylpropanolamine in plasma. 1987

A A Reid, and P J Fleming, and C R Lake

Department of Psychiatry, Uniformed Services University of the Health Sciences, F. Edward Hebert School of Medicine, Bethesda, Maryland 20814.

We modified a norepinephrine radioenzymatic method (C. R. Lake, M. G. Ziegler, and I. J. Kopin, 1976, Life Sci. 18, 1315-1326) for determination of plasma phenylpropanolamine (PPA) concentrations. PPA is converted to N[methyl-3H]ephedrine ([3H]EPD) by the enzyme phenylethanolamine N-methyltransferase (PNMT) and S-[methyl-3H]adenosyl-L-methionine ([3H]AdoMet). The product, [3H]EPD, is isolated from unreacted [3H]AdoMet and labeled side products by an organic extraction and a TLC procedure. In addition, a preincubation organic extraction procedure is included to remove inhibitors of PNMT from plasma and to concentrate the sample for enhanced enzymatic conversion. In order to accurately quantitate PPA across the wide range of possible concentrations, the assay is conducted at two plasma volumes. PPA concentrations between 0.3 and 50 micrograms/liter can be detected with 1 ml of plasma, while concentrations between 4 and 1500 micrograms/liter can be detected with 0.1 ml of plasma. The intra-assay coefficients of variation (CVs) are 9.3 and 5.7% at 0.5 and 1500 micrograms/liter, respectively, while the mean interassay CV is 13.8%.

UI	MeSH Term	Description	Entries
D007536	Isomerism	The phenomenon whereby certain chemical compounds have structures that are different although the compounds possess the same elemental composition. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)	Isomerisms
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D010625	Phenylethanolamine N-Methyltransferase	A methyltransferase that catalyzes the reaction of S-adenosyl-L-methionine and phenylethanolamine to yield S-adenosyl-L-homocysteine and N-methylphenylethanolamine. It can act on various phenylethanolamines and converts norepinephrine into epinephrine. (From Enzyme Nomenclature, 1992) EC 2.1.1.28.	Phenethanolamine N-Methyltransferase,Noradrenalin N-Methyltransferase,Noradrenaline N-Methyltransferase,Norepinephrine Methyltransferase,Norepinephrine N-Methyltransferase,Methyltransferase, Norepinephrine,Noradrenalin N Methyltransferase,Noradrenaline N Methyltransferase,Norepinephrine N Methyltransferase,Phenethanolamine N Methyltransferase,Phenylethanolamine N Methyltransferase
D010665	Phenylpropanolamine	A sympathomimetic that acts mainly by causing release of NOREPINEPHRINE but also has direct agonist activity at some adrenergic receptors. It is most commonly used as a nasal vasoconstrictor and an appetite depressant.	Norephedrine,Dexatrim,Phenylpropanolamine Hydrochloride,Prolamine,Propagest,Triaminic DM,Hydrochloride, Phenylpropanolamine
D011865	Radioisotope Dilution Technique	Method for assessing flow through a system by injection of a known quantity of radionuclide into the system and monitoring its concentration over time at a specific point in the system. (From Dorland, 28th ed)	Radioisotope Dilution Technic,Dilution Technic, Radioisotope,Dilution Technics, Radioisotope,Dilution Technique, Radioisotope,Dilution Techniques, Radioisotope,Radioisotope Dilution Technics,Radioisotope Dilution Techniques,Technic, Radioisotope Dilution,Technics, Radioisotope Dilution,Technique, Radioisotope Dilution,Techniques, Radioisotope Dilution
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D014316	Tritium	The radioactive isotope of hydrogen also known as hydrogen-3. It contains two NEUTRONS and one PROTON in its nucleus and decays to produce low energy BETA PARTICLES.	Hydrogen-3,Hydrogen 3