title: Kinetics of sodium-lithium countertransport in normotensive and hypertensive subjects.
abstract: The kinetic parameters Vmax and Km of erythrocyte sodium-lithium countertransport (Na-Li CT), and the lithium cell to plasma ratio (Li C:P) measured 24 h after a 1-g oral dose of Li2CO3, were determined in 14 normotensive (NT) and 14 untreated mild hypertensive (HT) males matched for age and weight. Li C:P and Na-Li CT were strongly correlated (r = -0.73), p less than 0.001), confirming the validity of Li C:P as an in vivo index of Na-Li CT. No differences in Li C:P (NT: 0.27 +/- 0.07; HT: 0.23 +/- 0.06), Na-Li CT (NT: 0.39 +/- 0.10 mmol/L/h; HT: 0.43 +/- 0.10 mmol/L/h), Vmax (NT: 0.58 +/- 0.16 mmol/L/h; HT: 0.68 +/- 0.20 mmol/L/h), or Km (NT: 1.5 +/- 0.4 mmol/L; HT: 1.6 +/- 0.9 mmol/L) were found between NT and HT. Our data do not support the marker concept of erythrocyte Na-Li CT in human hypertension.
authors.affiliation: Department of Medicine, Wellington School of Medicine, New Zealand.
authors.forename: R W
authors.initials: RW
authors.lastname: Siebers
authors.forename: T J
authors.initials: TJ
authors.lastname: Maling
mesh_terms: D000328:Adult; D001692:Biological Transport; D004912:Erythrocytes / Q000378:metabolism*; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000378:metabolism*; D066298:In Vitro Techniques; D007700:Kinetics; D008094:Lithium / Q000097:blood / Q000378:metabolism*; D008297:Male; D012964:Sodium / Q000097:blood / Q000378:metabolism*
chemical_list: D008094:Lithium; D012964:Sodium