Gc. Agnoli et al., Renal function and urinary prostanoid excretions in salt-depleted women: comparative effects of enalapril and indomethacin treatments, PROS LEUK E, 60(2), 1999, pp. 87-93
Citations number
20
Categorie Soggetti
Cell & Developmental Biology
Journal title
PROSTAGLANDINS LEUKOTRIENES AND ESSENTIAL FATTY ACIDS
The acute effects on urinary prostanoid excretion and on renal function ind
uced by pharmacological inhibition of either the angiotensin-converting enz
yme or of the cyclooxygenase system, respectively, have been studied in hea
lthy salt-depleted women. Two experimental groups were studied during salt
depletion, SD1 (n=8) and natriuretic and potassium sparing treatment. Paire
d studies were performed in the absence and in the presence of enalapril (S
D1 group) or indomethacin (SD2 group). In both paired studies renal functio
n was estimated by the clearance (cl.) method and the urinary concentration
s of PGE(2), 6-keto-PGF(1 alpha) and TXB2 were estimated by RIA during sust
ained hypotonic polyuria (induced by oral water load). Enalapril did not in
fluence urinary excretion of prostanoids. Its main significant effects were
: (a) a reduction in mean arterial pressure (MAP); (b) an increase ion free
-water cl. (C-H2O) and a reduction in osmolar cl. (C-osm); (c) a reduction
in the absolute and fractional urinary excretions of sodium and chloride; a
nd (d) a reduction in both the plasma concentration and urinary excretion o
f potassium. The urinary flow rate and the creatinine cl. were not signific
antly affected. Indomethacin reduced urinary excretion of prostanoids and i
n addition it produced the following significant effects: (a) a reduction i
n urinary flow rate, C-H2O and C-osm values, and in absolute and fractional
urinary excretions of sodium and chloride; and (b) an increase in plasma p
otassium concentration. MAP, creatinine cl. and urinary potassium excretion
were not significantly affected. With regard to the main parameters, both
enalapril and indomethacin exerted similar effects on urinary sodium and ch
loride excretion but opposite effects on C-H2O and plasma potassium concent
ration.
In conclusion, after enalapril in a salt-depleted state, the functional exp
ression of acute angiotensin II deprivation was partially masked by the act
ivation of a homeostatic system responsible both for improvement in renal s
alt conservation and for facilitated cellular potassium uptake. After indom
ethacin in the same setting, the results were consistent with a differentia
l role of prostanoids in modulating or mediating the activities of neuro-ho
rmonal agonists.