Comparison of the response of serum ceruloplasmin and cholesterol, and of tissue ascorbic acid, metallothionein, and nonprotein sulfhydryl in rats to the dietary level of cystine and cysteine.
The effects were compared of the addition of graded levels of L-cystine and of L-cysteine (0.3, 3, or 5%) to a 10% casein diet on several metabolic parameters in rats. The growth-promoting effect of cystine was equivalent to that of cysteine. Supplementation of these two amino acids elevated serum cholesterol, liver ascorbic acid, liver nonprotein sulfhydryl (SH) and kidney metallothionein, and reduced the activity of serum ceruloplasmin. The responses of serum cholesterol, liver nonprotein SH, and serum ceruloplasmin to cystine were greater than of those to cysteine. When the basal diet was supplemented with 0.3% of these amino acids, the elevation of liver ascorbic acid by cystine supplementation was less than that by cysteine supplementation. However, when supplemented with 5% of these amino acids, the elevation of liver ascorbic acid by cystine was greater than that by cysteine. There was no difference in the influence of cystine and cysteine on kidney metallothionein. This study demonstrates that dietary cystine and cysteine had the same influence on growth, but had a differential influence on such metabolic parameters as liver nonprotein SH, serum ceruloplasmin, serum cholesterol, and tissue ascorbic acid.
Yang
B S
BS
Department of Applied Biochemistry, Faculty of Applied Biological Science, Hiroshima University, Japan.
Yamazaki
M
M
Wan
Q
Q
Kato
N
N
D000818:Animals; D001205:Ascorbic Acid / Q000378:metabolism*; D002570:Ceruloplasmin / Q000378:metabolism*; D002784:Cholesterol / Q000097:blood*; D003545:Cysteine / Q000494:pharmacology*; D003553:Cystine / Q000494:pharmacology*; D004032:Diet; D004435:Eating; D008297:Male; D008668:Metallothionein / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013438:Sulfhydryl Compounds / Q000378:metabolism*; D017392:Thiobarbituric Acid Reactive Substances
D013438:Sulfhydryl Compounds; D017392:Thiobarbituric Acid Reactive Substances; D003553:Cystine; D008668:Metallothionein; D002784:Cholesterol; D002570:Ceruloplasmin; D003545:Cysteine; D001205:Ascorbic Acid