The effect of enalapril and sairei-to on survival-time for the rat with subtotal nephrectomy.

The effect of an angiotensin-converting enzyme inhibitor, enalapril, and a Japanese medicinal plant named sairei-to, after administration either alone or in combination, on survival-time due to the protection of proteinuria and the preserving of renal function, was studied in the rat with subtotal nephrectomy. Resection of 2/3 of the left kidney and removal of the right kidney was performed in 28 male Wister rats (220-250 g). The rats were divided into four groups: (1) control (without sairei-to or enalapril); (2) with sairei-to (2.5% in rat chow); (3) with enalapril (50 mg/l in drinking water); and (4) the combination of enalapril and sairei-to. The actual survival-times until natural death after renal ablation in these four groups were 92 +/- 3, 128 +/- 8, 199 +/- 19, and 194 +/- 13 days, respectively. Urinary protein excretion and renal function were markedly protected in the enalapril-treated rats. Urinary endothelin excretion was also attenuated in enalapril-treated rats. Statistical analysis revealed the absence of benefits with sairei-to alone or in combination treatment. In conclusion, enalapril provides protection of proteinuria and preserves renal function, which results in a longer survival-time in the rats having subtotal nephrectomy. However, sairei-to does not show such beneficial effects.