title: Salt, endogenous ouabain and blood pressure interactions in the general population.
abstract: OBJECTIVE
  Experimental data show that ouabain is a modulator of the sodium-potassium pump, which plays an important role in sodium homeostasis and blood pressure regulation. We investigated the distribution of plasma ouabain in the general population in relation to blood pressure and other determinants of sodium homeostasis.
  
  
  METHODS
  In 379 subjects enrolled in a Belgian population study, we measured plasma ouabain, clinical characteristics including blood pressure, serum and urinary electrolytes, urinary aldosterone excretion, various lifestyle factors, and the Gly460Trp polymorphism of the alpha-adducin gene. Our statistical methods included analysis of covariance and multiple linear regression.
  
  
  RESULTS
  Plasma ouabain (median, 140 pmol/l) correlated independently and positively with male gender (n = 182, P = 0.002), smoking (n = 116, P = 0.05), urinary potassium excretion (mean 69 mmol/day, P < 0.0001), and mutation of the alpha-adducin gene (n = 161, P < 0.0001). Both before and after adjustment for covariables, continuous as well as categorical analyses revealed a significant interaction (P < or = 0.02) between plasma ouabain and urinary sodium excretion (mean 194 mmol/day) in relation to blood pressure (mean systolic blood pressure/diastolic blood pressure, 123/76 mmHg). In individuals with plasma ouabain values below the median, blood pressure increased by 2.2 mmHg systolic and 1.4 mmHg diastolic for each 50 mmol/day increment in urinary sodium excretion (P < or = 0.01). No association between blood pressure and urinary sodium excretion was found when plasma ouabain exceeded the median.
  
  
  CONCLUSIONS
  Plasma ouabain behaves as a blood pressure modulating factor, possibly released in response to potassium, either inhibiting the pressor effect of an excessive salt intake or counteracting the depressor action of sodium depletion.
authors.affiliation: Hypertensie en Cardiovasculaire Revalidatie Eenheid, Departement voor Moleculair en Cardiovasculair Onderzoek, Katholieke Universiteit Leuven, Leuven, Belgium.
authors.forename: Ji-Guang
authors.initials: JG
authors.lastname: Wang
authors.forename: Jan A
authors.initials: JA
authors.lastname: Staessen
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Messaggio
authors.forename: Tim
authors.initials: T
authors.lastname: Nawrot
authors.forename: Robert
authors.initials: R
authors.lastname: Fagard
authors.forename: John M
authors.initials: JM
authors.lastname: Hamlyn
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Bianchi
authors.forename: Paolo
authors.initials: P
authors.lastname: Manunta
mesh_terms: D000328:Adult; D001794:Blood Pressure / Q000502:physiology*; D002148:Calmodulin-Binding Proteins / Q000235:genetics; D002298:Cardenolides; D004077:Digoxin / Q000097:blood*; D005260:Female; D005787:Gene Frequency; D006706:Homeostasis; D006801:Humans; D006973:Hypertension / Q000097:blood* / Q000235:genetics / Q000652:urine; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D011188:Potassium / Q000652:urine; D011897:Random Allocation; D012503:Saponins / Q000097:blood*; D012964:Sodium / Q000652:urine; D017673:Sodium Chloride, Dietary; D000099291:Adducins
chemical_list: D002148:Calmodulin-Binding Proteins; D002298:Cardenolides; D004077:Digoxin; D011188:Potassium; D012503:Saponins; D012964:Sodium; D017673:Sodium Chloride, Dietary; D000099291:Adducins; C034504:digoxin-like factors