Recovery of erythrocyte Na(+)-K(+)-Cl- cotransport activity by enalapril.
We studied total exchangeable sodium, ion transport activity at maximal rate, and erythrocyte Na+ content in response to angiotensin converting enzyme inhibition in mild-to-moderate essential hypertensive patients with normal renal function. Twenty-five patients (mean age 56 years, range 40-62 years) who had abnormal red blood cell Na(+)-K(+)-Cl- cotransport or red blood cell Li(+)-Na+ countertransport were treated with either enalapril (20 mg daily) or hydrochlorothiazide (50 mg daily) during a 30-day period. During the period of enalapril treatment, Na(+)-K+ pump and Na(+)-K(+)-Cl- cotransport increased significantly from 4,282 +/- 255 to 5,236 +/- 325 mumol/l red blood cell/hr (p less than 0.01) and 166 +/- 21 to 220 +/- 24 mumol/l red blood cell/hr (p less than 0.05), respectively. Mean intracellular Na+ content in erythrocytes decreased from 11.4 +/- 0.40 to 10.0 +/- 0.33 mmol/l (p less than 0.01) and exchangeable Na+ from 39.8 +/- 0.6 mmol/kg to 35.6 +/- 0.6 mmol/kg (p less than 0.001). Sodium reduction correlated with the recovery of Na(+)-K(+)-Cl- cotransport activity (r = -0.65, p less than 0.01). During treatment, systolic and diastolic blood pressures were reduced significantly (p less than 0.01). In 12 patients treated with hydrochlorothiazide, Na(+)-K(+)-Cl- cotransport, Na(+)-K+ pump, Na(+)-Li+ countertransport, and Na+ permeability did not change significantly while Na+ content decreased from 11.7 +/- 0.3 to 10.3 +/- 0.2 mmol/l (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
Sanchez
R A
RA
Hypertension Division, Academia Nacional de Medicina, Buenos Aires, Argentina.
Gimenez
M I
MI
Gilbert
B H
BH
Giannone
C
C
Marco
E J
EJ
Ramirez
A J
AJ
D000328:Adult; D001692:Biological Transport / Q000187:drug effects; D002712:Chlorides / Q000097:blood*; D004656:Enalapril / Q000494:pharmacology*; D004912:Erythrocytes / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011188:Potassium / Q000097:blood*; D012964:Sodium / Q000097:blood*
D002712:Chlorides; D004656:Enalapril; D012964:Sodium; D011188:Potassium