title: Highly sensitive and specific HPLC with fluorometric detection for determination of plasma epinephrine and norepinephrine applied to kinetic studies in humans.
abstract: An HPLC separation method combined with fluorometric detection was extended to enable simultaneous assessment of plasma 3H-labeled and endogenous epinephrine (E) and norepinephrine (NE). Forearm fractional extraction (FFE) of 3H-labeled E and NE and of endogenous E was measured in 40 healthy volunteers who were receiving a continuous infusion of 3H-labeled E and NE. Concentrations of arterial and venous E were 26.8 +/- 1.95 (mean +/- SE) and 6.8 +/- 0.75 ng/L, respectively. Arterial and venous NE and dopamine (DA) were also measured, with respective values of 140.7 +/- 8.5 and 192.1 +/- 15.1 for NE, and 13.1 +/- 0.78 and 11.3 +/- 0.70 ng/L for DA. The FFE of 3H-labeled E was slightly but significantly higher (0.790 +/- 0.016) than the that of either 3H-labeled NE or endogenous E (0.748 +/- 0.0146 and 0.745 +/- 0.0185, respectively; P < 0.001), the correlations being highly significant (r = 0.80, P < 0.001) in both cases. The small difference between the FFE of E and of 3H-labeled E allows the calculation of the apparent spillover of E. However, this spillover was negligible compared with forearm NE spillover (0.0112 +/- 0.0031 vs 1.369 +/- 0.128 ng/L per minute. The high sensitivity of this measurement of venous E widens the possibilities for studying E kinetics under physiological conditions.
authors.affiliation: Department of Experimental and Chemical Endocrinology, Academic Hospital St. Raboud, University of Nijmegen, The Netherlands.
authors.forename: J J
authors.initials: JJ
authors.lastname: Willemsen
authors.forename: H A
authors.initials: HA
authors.lastname: Ross
authors.forename: M C
authors.initials: MC
authors.lastname: Jacobs
authors.forename: J W
authors.initials: JW
authors.lastname: Lenders
authors.forename: T
authors.initials: T
authors.lastname: Thien
authors.forename: L M
authors.initials: LM
authors.lastname: Swinkels
authors.forename: T J
authors.initials: TJ
authors.lastname: Benraad
mesh_terms: D000328:Adult; D001158:Arteries; D002851:Chromatography, High Pressure Liquid / Q000379:methods* / Q000706:statistics & numerical data; D004298:Dopamine / Q000097:blood; D004837:Epinephrine / Q000097:blood*; D006801:Humans; D007545:Isoproterenol / Q000097:blood; D007700:Kinetics; D009638:Norepinephrine / Q000097:blood*; D012680:Sensitivity and Specificity; D014316:Tritium; D014680:Veins
chemical_list: D014316:Tritium; D007545:Isoproterenol; D004298:Dopamine; D009638:Norepinephrine; D004837:Epinephrine