title: Delayed increase in blood pressure induced by spontaneously hypertensive rat plasma after high sodium intake.
abstract: Plasma from spontaneously hypertensive rats (SHR) and from patients with essential hypertension has been suggested to contain a substance with a delayed pressor effect, parathyroid hypertensive factor (PHF), associated with salt-sensitive forms of hypertension. In order to study whether high sodium intake would increase plasma levels of PHF-like activity, determined by bioassay, SHR received either a high-sodium (2.6% Na in the chow) or a normal-sodium (0.3% Na) diet for 6 weeks. Intravenous injection of plasma from SHR on a high-sodium diet (6 ml/kg) to urethane-anaesthetized Wistar rats induced a delayed increase in mean arterial blood pressure 70-80 min after bolus injection. No delayed pressor effects could be demonstrated by plasma from SHR or Wistar rats on a normal-sodium diet. It is concluded that a factor with a delayed blood pressure-increasing effect appears to be present in plasma from SHR on a high-sodium diet but not in plasma from normotensive Wistar rats or SHR on a normal-sodium diet. Further studies to characterize this factor and its possible relation to salt-induced hypertension are warranted.
authors.affiliation: Department of Medicine, Helsinki University Central Hospital, Finland.
authors.forename: I
authors.initials: I
authors.lastname: Tikkanen
authors.forename: T L
authors.initials: TL
authors.lastname: Teräväinen
authors.forename: E
authors.initials: E
authors.lastname: Mervaala
authors.forename: H
authors.initials: H
authors.lastname: Karppanen
mesh_terms: D000818:Animals; D001685:Biological Factors / Q000008:administration & dosage* / Q000097:blood; D001794:Blood Pressure / Q000187:drug effects*; D001798:Blood Proteins / Q000008:administration & dosage; D006801:Humans; D006973:Hypertension / Q000097:blood* / Q000503:physiopathology; D008297:Male; D051381:Rats; D011918:Rats, Inbred SHR; D017208:Rats, Wistar; D017673:Sodium Chloride, Dietary / Q000008:administration & dosage*
chemical_list: D001685:Biological Factors; D001798:Blood Proteins; D017673:Sodium Chloride, Dietary; C064505:parathyroid hypertensive factor