REDUCTION OF RENAL TRANSFORMING GROWTH-FACTOR-BETA ACTIVITY WITHOUT AGGRAVATION OF GROWTH-RETARDATION IN NEPHRITIC RATS BY A METHIONINE-THREONINE-SUPPLEMENTED LOW-CASEIN DIET

The effects of a low-casein diet fortified with methionine and threoni ne on renal cortical and glomerular transforming growth factor (TGF)-b eta activity were studied in rats with nephritis induced by anti-rat k idney glomerular basement membrane antiserum, Both normal and nephriti c rats were fed experimental diets for 10 days, An injection of nephro toxic serum increased urinary protein excretion and renal TGF-beta act ivity, A methionine-threonine-supplemented 8.5% casein diet, compared with a basal 20% casein diet, decreased these two measurements without aggravating growth retardation in nephritic rats, These results sugge st that aggravation and alleviation of symptoms incident to anti-GBM n ephritis are relevant to elevation and reduction of TGF-beta activity, respectively, The results also suggest that amino acid-balanced low-p rotein diets would have beneficial effects on glomerulonephritis witho ut causing severe protein malnutrition.