Higher plasma Na+,K+-ATPase inhibitory activity in essential hypertensive patients.
The ability of plasma to inhibit 86 rubidium uptake in rat aorta and to displace [3H]-ouabain from hog brain Na+,K+-ATPase was used as a measure of plasma Na+,K+-ATPase inhibitory activity in seven normotensive and eight hypertensive subjects. Rat aortae rings were incubated in oxygenated plasma containing 86 rubidium (2 microCi/mL) for 30 mins at 37 degrees C and uptake measured and expressed as mumol/kg wet weight/min. Plasma was extracted with a mixture of chloroform and methanol (2:1) and the extract separated by silicic acid column followed by thin layer chromatography and fractions assayed for ouabain displacement using digoxin as a standard. Total ouabain displacement was calculated as the sum of all fractions. There was a strong correlation between the two methods for total plasma Na+,K+-ATPase inhibitory activity (r = 0.761, P less than 0.01). There was a significant positive correlation between plasma Na+,K+-ATPase inhibitory activity and blood pressure in all subjects. Na+,K+-ATPase inhibitory activity was significantly higher in plasma of hypertensives by both methods (P less than 0.001). The increased Na+,K+-ATPase inhibitory activity in plasma from hypertensives was due to the nonesterified fatty acid, long chain acylcarnitine and diphosphatidylglycerol fractions.
Vasdev
S
S
Department of Medicine, Memorial University of Newfoundland, St John's.
Fernandez
P G
PG
Longerich
L
L
Gault
H
H
D000328:Adult; D000818:Animals; D001794:Blood Pressure; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010042:Ouabain / Q000378:metabolism; D051381:Rats; D012414:Rubidium Radioisotopes / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors* / Q000097:blood
D012414:Rubidium Radioisotopes; D010042:Ouabain; D000254:Sodium-Potassium-Exchanging ATPase