title: Interaction of internal Na+ and external K+ with the erythrocyte Na+, K+ cotransport system in essential hypertension.
abstract: External K+ inhibits the maximal rate of outward Na+, K+ cotransport in human red cells with no effect on the apparent affinity for internal Na+. The K+ concentration giving half-maximal inhibition (KIK) varied from 16 to 30 mM in 24 normotensive control subjects. Six of the 38 hypertensive patients showed a KIK above the upper limit of this normal range. Only three hypertensive patients showed a KIK below normal range. The internal Na+ content giving half-maximal stimulation of outward Na+, K+ cotransport (KSNa) was measured in the hypertensive patients (a normal range of KSNa = 9 to 16 mmol/liter cells was previously established in 50 normotensive control subjects). Eighteen hypertensive patients showed an abnormally high KSNa, as previously described in hypertensive patients whose Na+, K+ cotransport system had a low affinity for internal Na+ (Co -). Comparison of KSNa with KIK showed that all six hypertensive patients with high KIK and all three hypertensive patients with low KIK were Co - hypertensive.
mesh_terms: D000328:Adult; D001692:Biological Transport; D002586:Cesium / Q000494:pharmacology; D004912:Erythrocytes / Q000378:metabolism*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood* / Q000503:physiopathology; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D011188:Potassium / Q000097:blood*; D012413:Rubidium / Q000494:pharmacology; D012964:Sodium / Q000097:blood*
chemical_list: D002586:Cesium; D012964:Sodium; D008274:Magnesium; D012413:Rubidium; D011188:Potassium