Renal adaptation to sodium deprivation. Effect of captopril in the rat.
Dietary sodium restriction is associated with a rapid decrease in urinary sodium excretion and achievement of a new sodium balance within three to five days. In addition, renal vasoconstriction and progressive activation of intrarenal systems with vasoconstrictor (renin-angiotensin) or vasodilating (kallikrein-kinin and prostaglandins) properties are observed. The relationship between sodium homeostasis and the renin-angiotensin system was assessed through the use of captopril in the rat. Treatment with captopril, before and during a six-day period after suppression of dietary sodium, was associated with sodium wasting (urinary sodium always exceeded sodium intake during the observation period); in addition, the normal increase in urinary aldosterone was blunted by about 80 percent. When captopril treatment was given for six days to rats maintained on long-term sodium restriction (at least four weeks) urinary sodium increased, although transiently; at the end of the study, renal vasodilatation together with a redistribution of glomerular blood flow to nonsuperficial glomeruli was observed. These studies indicate that captopril administration markedly blunts the renal and systemic adaptations to a reduced sodium intake in the rat. They suggest that the renin-angiotensin system is probably indispensable in preventing sodium loss when dietary sodium is suppressed.
D000222:Adaptation, Physiological / Q000187:drug effects; D000806:Angiotensin-Converting Enzyme Inhibitors; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002216:Captopril / Q000494:pharmacology*; D004039:Diet, Sodium-Restricted; D007668:Kidney / Q000187:drug effects* / Q000502:physiology; D009318:Natriuresis / Q000187:drug effects; D011392:Proline / Q000031:analogs & derivatives*; D051381:Rats; D012077:Renal Artery / Q000187:drug effects; D012079:Renal Circulation / Q000187:drug effects; D012082:Renal Veins / Q000187:drug effects; D012084:Renin-Angiotensin System / Q000187:drug effects*; D012504:Saralasin / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism; D012965:Sodium Chloride / Q000008:administration & dosage; D013997:Time Factors; D014664:Vasodilation / Q000187:drug effects; D014882:Water-Electrolyte Balance / Q000187:drug effects*
D000806:Angiotensin-Converting Enzyme Inhibitors; D012965:Sodium Chloride; D011392:Proline; D002216:Captopril; D012964:Sodium; D012504:Saralasin