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Abnormal glomerular and tubular function during angiotensin converting enzyme inhibition in renovascular hypertension evaluated by the lithium clearance method
Author(s) -
PEDERSEN E.B.,
SØRENSEN S. S.,
AMDISEN A.,
DANIELSEN H.,
EISKJÆR H.,
HANSEN H. H.,
JENSEN F.T.,
JESPERSEN B.,
MADSEN B.,
NIELSEN H. K.
Publication year - 1989
Publication title -
european journal of clinical investigation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.164
H-Index - 107
eISSN - 1365-2362
pISSN - 0014-2972
DOI - 10.1111/j.1365-2362.1989.tb00207.x
Subject(s) - captopril , renovascular hypertension , medicine , endocrinology , reabsorption , chemistry , renal function , renal sodium reabsorption , plasma renin activity , essential hypertension , angiotensin ii , blood pressure , aldosterone , renin–angiotensin system , kidney
. Glomerular filtration rate (GFR) and tubular function were measured by means of the lithium clearance technique in 14 patients with renovascular hypertension (RVH) and eight patients with essential hypertension (EH) before and after oral administration of captopril 25 mg. In RVH captopril reduced 51‐Cr‐EDTA clearance (67.3 (median) to 47.5 ml min ‐1 , P <0.01), proximal absolute reabsorption of fluid (53.9 to 41.5 ml min ‐1 , P <0.01) and distal absolute reabsorption of sodium (2195 to 1402 μmol min ‐1 , P <0.01), whereas proximal fractional reabsorption increased slightly (77.5 to 80.2%, P <0.02). In EH, however, these parameters were practically unaffected by captopril. In both RVH and EH plasma concentrations of angiotensin II and aldosterone were reduced after captopril, but atrial natriuretic peptide in plasma and urinary excretion rate of prostaglandin E 2 were unchanged. Blood pressure decreased after captopril in both groups, but the maximum fall in systolic BP was more pronounced in RVH (22%) than EH (13%). It is concluded that angiotensin converting enzyme inhibition markedly reduced absolute reabsorption in both the proximal and distal tubules in RVH, in contrast to EH, predominantly due to fall in the GFR, and that the slight increase in proximal fractional reabsorption may be attributed to a reduction in the hydrostatic pressure in the peritubular vessels.