Opposite effects of enalapril and nitrendipine on natriuretic response to atrial natriuretic factor. Renal function evaluated with clearance studies in humans.
In clearance studies, we analyzed the effect of Ca2+ entry blockade with nitrendipine treatment (20 mg b.i.d. for 4 days) and of converting enzyme inhibition with enalapril treatment (20 mg b.i.d. for 4 days) on renal response to atrial natriuretic factor (ANF) (25 micrograms bolus followed by an infusion of 0.03 microgram/kg/min for 90 minutes) in six healthy volunteers who were taking 300 mmol sodium daily. In a control study ANF was administered without Ca2+ entry blockade or converting enzyme inhibition. Natriuresis rose from 239 +/- 38 to 605 +/- 137 mumol/min in the control study (p less than 0.05), from 330 +/- 53 to 943 +/- 152 mumol/min with Ca2+ entry blockade (p less than 0.05), and from 236 +/- 22 to 344 +/- 39 mumol/min with converting enzyme inhibition (NS). ANF induced a rise in maximal free water clearance, inulin clearance, and in the excretion of multiple electrolytes except potassium. Fractional lithium reabsorption fell. In general, these effects were stronger during Ca2+ entry blockade and blunted during converting enzyme inhibition. p-Aminohippurate clearance tended to decrease during the control study (NS), remained constant during Ca2+ entry blockade, and decreased significantly when ANF was infused during converting enzyme inhibition (p less than 0.05 vs. control and vs. Ca2+ entry blockade study). Blood pressure was lowered by Ca2+ entry blockade and, to a somewhat greater extent, by converting enzyme inhibition, but ANF administration induced no additional fall except for a short-term drop during Ca2+ entry blockade.(ABSTRACT TRUNCATED AT 250 WORDS)
Gaillard
C A
CA
Department of Nephrology, University Hospital Utrecht, The Netherlands.
Koomans
H A
HA
Rabelink
T J
TJ
Boer
P
P
Dorhout Mees
E J
EJ
D000328:Adult; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D004656:Enalapril / Q000494:pharmacology*; D005919:Glomerular Filtration Rate / Q000187:drug effects; D006801:Humans; D007668:Kidney / Q000187:drug effects*; D008297:Male; D009568:Nitrendipine / Q000494:pharmacology*; D012964:Sodium / Q000652:urine*
D004656:Enalapril; D009320:Atrial Natriuretic Factor; D009568:Nitrendipine; D012964:Sodium