Urinary excretion of dimethylarginines in premature infants.
Urinary excretion of NG,N'G-dimethylarginine (NG,N'G-Me2Arg) and NG,NG-dimethylarginine (NG,NG-Me2Arg) was measured in premature infants. The NG,N'G-Me2Arg/NG,NG-Me2Arg ratio was much higher in newborn infants than in older children or adults. Linear regression analysis showed a significant negative correlation between the degree of maturity and the excretion of NG,N'G-Me2Arg. A significant direct linear relationship also was found between the excretion of NG,N'G-Me2Arg and the rate of whole body nitrogen flux and of protein synthesis and catabolism. No correlation was found between the excretion of the dimethylarginines and 3-methylhistidine, but the dimethylarginine/3-methylhistidine ratio declined with advancing conceptual age. A direct linear relationship was found between excretion of NG,N'G-Me2Arg and NG,NG-Me2Arg and whole body nonskeletal muscle protein breakdown. No correlation was found between nonskeletal muscle protein catabolism and 3-methylhistidine excretion. We estimate that approximately 0.34 mumole of dimethylarginine are excreted per gram of nonskeletal muscle protein catabolized. Dietary intake did not affect the excretion of either NG,N'G-Me2Arg or NG,NG-Me2Arg. The data suggest that measurement of urinary dimethylarginines might be useful in the nutritional assessment of premature infants.
D000293:Adolescent; D000328:Adult; D000375:Aging; D001120:Arginine / Q000031:analogs & derivatives* / Q000652:urine; D001835:Body Weight; D002648:Child; D002675:Child, Preschool; D004032:Diet; D005865:Gestational Age; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature; D008297:Male; D008762:Methylhistidines / Q000652:urine; D009124:Muscle Proteins / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D011506:Proteins / Q000378:metabolism
D008762:Methylhistidines; D009124:Muscle Proteins; D011506:Proteins; C024917:symmetric dimethylarginine; C018524:N,N-dimethylarginine; D001120:Arginine; C028118:3-methylhistidine; D009584:Nitrogen