Reduction of hyperlipidemia and proteinuria without growth retardation in nephritic rats by a methionine-supplemented, low-soy-protein diet.

Effect of a low-soy-protein-isolate (SPI) diet supplemented with methionine on hyperlipidemia, proteinuria, and hypoalbuminemia was studied in rats with nephrotoxic serum nephritis (NSN). Rats were fed experimental diets for 14 d after an injection of nephrotoxic serum. An 8.5%-SPI diet (8.5S), as compared with a basal 20%-SPI diet (20S), improved the hyperlipidemia, proteinura, and hypoalbuminemia secondary to NSN but retarded the growth of rats. The addition of 0.3% methionine to 8.5S (8.5SM) alleviated the growth retardation without loss of the above-mentioned beneficial effects. 8.5SM was found to suppress hepatic cholesterol synthesis compared with 20S. These results suggest that the methionine-supplemented low-SPI diet has a beneficial effect on hyperlipidemia, proteinuria, and hypoalbuminemia without inducing either growth retardation or severe fatty liver in nephritis. They also suggest that the hypocholesterolemic effect of 8.5SM in nephritic rats may be partly attributable to reduced hepatic cholesterol synthesis.