The present study investigated the effect of enalapril on the glomerular sieving coefficient of albumin (GSCA) using intravital multiphoton microscopy. Munich Wistar Frömter (MWF) rats were used as a model of hypertension-related glomerular lesions. Young rats were nonproteinuric; however, the urinary albumin excretion gradually increased during aging, averaging 0.00062 mg/mOsmol per liter at the age of 9 weeks and 0.0054 mg/mOsmol per liter at 52 weeks. The albuminuria in aged MWF rats was accompanied by structural changes, which were indicative of glomerular lesions. The GSCA was low in young rats but increased markedly during aging, averaging 0.00057 in young and 0.0027 in 52-week-old rats. The treatment of proteinuric 12-month-old rats with enalapril over a 4-week-period reduced the GSCA from 0.0027 to 0.00139. Similarly, the urinary albumin excretion was reduced from 0.0051 to 0.0036 mg/mOsmol per liter. These data suggest that glomerular, rather than tubular, mechanisms account for the beneficial antiproteinuric effects of the ACE inhibitor.
See article at J Pharmacol Exp Ther 2015, 353:299–306.
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