Long-term effects of antihypertensive regimens on renal hemodynamics and proteinuria.

The long-term effects of different antihypertensive regimens were studied in uninephrectomized beagles with alloxan-induced diabetes mellitus. Mean arterial pressure (MAP) was elevated (P < 0.05) in untreated diabetic dogs. Treatment of diabetic dogs with an angiotensin converting enzyme inhibitor (ACEI; lisinopril), a calcium antagonist (CA;TA-3090), or both lowered MAP. At one year, the RBF, GFR, and SNGFR were similarly elevated (P < 0.05) in all groups of diabetic dogs. The increase in SNGFR present in untreated diabetic dogs was primarily attributable to an increased (P < 0.05) glomerular capillary pressure (PGC). Treatment with lisinopril lowered the PGC to a mean value that was indistinguishable from that for nondiabetic dogs. In contrast, diabetic dogs treated with TA-3090 had an elevated PGC. While untreated diabetic dogs exhibited marked increases in glomerular volume (P < 0.05 vs. nondiabetic dogs), treatment with lisinopril and TA-3090, either alone or in combination, blunted the extent of glomerular hypertrophy observed in diabetic dogs (P < 0.05 vs. untreated diabetic dogs). Proteinuria was similarly reduced (P < 0.05 vs. untreated diabetic dogs) in dogs treated with lisinopril and TA-3090. Combination therapy of diabetic dogs produced a further significant (P < 0.05) decrement in proteinuria. We conclude that although treatment of diabetic dogs with either lisinopril or TA-3090 results in differential effects on PGC; each produces a similar decrement in proteinuria. Further, combination therapy has a greater effect on proteinuria than either agent alone.(ABSTRACT TRUNCATED AT 250 WORDS)