Effect of dietary protein intake and angiotensin converting enzyme inhibition in Heymann nephritis

The effect of diets containing 8.5%, 21% or 40% protein on growth, urinary albumin excretion and serum albumin concentration was determined in rats with Heymann nephritis and in non-nephrotic control animals. Urinary albumin excretion was greater in nephrotic rats with each increment in dietary protein intake, and serum albumin concentration tended to be least in nephrotic rats fed 40% protein. Albuminuria decreased spontaneously and serum albumin concentration increased in nephrotic rats fed 8.5% protein for 25 days. Enalapril treatment caused a further reduction in urinary albumin excretion and an increase in serum albumin concentration in nephrotic rats fed 8.5% protein. Albuminuria did not decrease nor did serum albumin concentration increase in nephrotic rats fed 40% protein without enalapril treatment, but enalapril caused a significant reduction in urinary albumin excretion and an increase in serum albumin concentration in nephrotic rats fed either 8.5% or 40% protein. The rate of growth in normal rats was greatest when they were fed 21% protein, compared to either 8.5% or 40% protein. Growth rate was significantly reduced in nephrotic rats, regardless of dietary protein intake and regardless of treatment with enalapril, but the 21% protein diet still induced the most rapid rate of growth. Growth rate was not significantly different in nephrotic rats fed either 40% or 8.5% protein. The difference in weight between pair fed nephrotic and control animals fed 21% protein was due to a decrease in carcass and skin weight in nephrotic animals. Carcass protein was significantly reduced in the nephrotic animals, and carcass saponafiable fat tended to be reduced.(ABSTRACT TRUNCATED AT 250 WORDS)