| Abstract: | The relationship between sodium homeostasis and the renin-angiotensin system was assessed through the use of two angiotensin-converting enzyme inhibitors (captopril and enalapril) in the rat. Treatment with captopril (group SQ) or enalapril (group MK) before and during a 6-day period of sodium free diet was associated with sodium wasting; on the sixth day of sodium restriction, sodium excretion was 164 +/- 17 and 144 +/- 10 mumol/24 h in SQ and MK group respectively. In addition, the cumulative Na+ excretion during the 6 day period of sodium-free diet was 1.04 +/- 0.07 mmoles in untreated rats and 1.70 +/- 0.13 and 1.86 +/- 0.14 mmoles in MK and SQ group respectively. At the end of the study, mean arterial pressure was lower in treated than in untreated animals. These findings show that in rats both renal and systemic adaptations to reduced sodium intake are markedly impaired by administration of converting enzyme inhibitors. |
