TY - JOUR T1 - APPLICATION OF THE ENZYMATIC DOUBLE ISOTOPE DILUTION ASSAY FOR THE STUDY OF HISTAMINE IN PLASMA JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 228 LP - 234 VL - 175 IS - 1 AU - RUSSELL L. MILLER AU - CLAY MCCORD AU - MICHELE SANDA AU - HENRY R. BOURNE AU - KENNETH L. MELMON Y1 - 1970/10/01 UR - http://jpet.aspetjournals.org/content/175/1/228.abstract N2 - Physiologic concentrations of histamine in human plasma can be detected easily and reliably by the use of a double isotope dilution technique. The extraction of histamine from plasma results in a mean recovery of 52% (S.D. ± 23). The extraction of histamine, which is isolated from guinea-pig brain, transfers C14 from C14-S-adenosylmethionine to tritium-labeled and cold histamine. The method, based on an assay previously described for tissue histamine, is rapid (up to 12 samples can be measured in eight hours), sensitive (lower limit, 03 ng/ml), reproducible, linear (from 0.3 to 100 ng/ml) and specific. Samples of plasma can be stored several weeks at —20°C without appreciable loss of histamine. Normal human concentrations range from 0.4 to 1.0 ng/ml with a mean of 0.61 ± 02 ng/ml. © 1970, by The Williams & Wilkins Company ER -