Influence of the timing of initiating antihypertensive therapy in hypertensive rats with renal failure

The important contribution of hypertension to the progression of renal fail ure is well realized. However, it have been less discussed which drugs are suitable for the different stages of progressive renal failure. The present study examined the effects of timing of antihypertensive therapy using cal cium channel blocker and angiotensin converting enzyme inhibitor in 5/6 nep hrectomized spontaneously hypertensive rats (SHRs). Forty male 6 week old S HRs were divided into 5 groups (n=8 in each group), and they were placed on a high salt diet after 5/6 nephrectomy. Group I, high salt diet without an y drug. Group 2 received 0.2 mg/kg/day of amlodipine and group 3 received 0 .2 mg/kg/day of enalapril mixed in the high salt diet from week 6 respectiv ely. Similarly group 4 received the same doses of amlodipine, and group 5 r eceived the same doses of enalapril from week 10. Each drug protected from increasing blood pressure in 4 groups, and no significant difference was ob served between the effects of amlodipine and enalapril. Proteinuria was red uced with both drugs. In histopathological evaluation, glomerulosclerosis w as controlled only in group 2, and arterio/olosclerosis was significantly s uppressed in all treated groups except group 5. From these results, both am lodipine and enalapril are renal protective in early stage of renal failure with hypertension. However, in advanced stage of renal failure, amlodipine is superior in its renal protective effect.