Mechanisms of adaptation to proteinuria in adriamycin nephrosis.
To evaluate the impact of urinary protein losses on whole body protein turnover (WBPT) independent of acidosis or uremia, we utilized a model of unilateral adriamycin nephrosis. Control rats were matched by weight to nephrotic rats and pair fed 22% protein chow for 14-18 days; urinary urea nitrogen (UUN) was measured on day 12, and leucine turnover measurement was performed on the final day. Growth rates of nephrotic and pair-fed control rats did not differ during the first 2 wk of pair feeding; thereafter, a small difference in growth could be detected. Despite an identical intake of dietary protein, UUN excretion was 29% less in the nephrotic rats (P < or = 0.02). Fasting whole body protein synthesis and degradation did not differ between nephrotic and control rats; in contrast, leucine oxidation decreased by 21% in nephrosis (P < 0.05). On the basis of near normal growth and normal rates of WBPT, we conclude that nephrotic rats fed ad libitum can adapt to the stress of continuous protein losses. A reduction in amino acid oxidation and UUN excretion were the primary mechanisms responsible for protein conservation in experimental nephrosis.
Choi
E J
EJ
Department of Medicine, Emory University School of Medicine, Atlanta, Georgia 30322.
May
R C
RC
Bailey
J
J
Masud
T
T
Dixon
A
A
Maroni
B J
BJ
D000818:Animals; D002245:Carbon Dioxide; D004317:Doxorubicin; D007930:Leucine / Q000097:blood; D008297:Male; D009401:Nephrosis / Q000097:blood / Q000139:chemically induced / Q000378:metabolism* / Q000652:urine*; D009584:Nitrogen / Q000652:urine; D011507:Proteinuria / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012119:Respiration; D014508:Urea / Q000652:urine
D002245:Carbon Dioxide; D004317:Doxorubicin; D014508:Urea; D007930:Leucine; D009584:Nitrogen