Protein metabolism kinetics in neonates: effect of intravenous carbohydrate and fat.
The aim of this study was to determine the effect of different glucose/fat ratios on protein metabolism kinetics in newborn infants receiving total parenteral nutrition (TPN). Eighteen studies were done on 14 infants receiving TPN (weight 3.15 +/- 0.22 kg [mean +/- SEM]; gestational age 37.8 +/- 0.9 weeks; postnatal age 14.0 +/- 3.7 days). There were two study groups. Group A infants (n = 9) received 10.0 g/kg/d of dextrose and 4.0 g/kg/d of fat; group B infants (n = 9) received 19.0 g/kg/d of dextrose and 0.5 g/kg/d of fat. Caloric intake (86 kcal/kg/d) and amino-acid intake (2.5 g/kg/d) were the same in the two groups. There was no difference between the groups with regard to weight, gestational age, and postnatal age. Intravenous diet was constant during the 3-day study period. Timed urinary nitrogen excretion was determined. On day 3 of the study, each infant received a priming dose of 15 mumol/kg of [13C]leucine followed by a 6-hour infusion at 6 mumol/kg/h. Plasma and breath samples were taken at hourly intervals, and CO2 production was measured by indirect calorimetry. Plateau levels of plasma [13C]-alpha Ketoisocaproic acid (KIC) enrichment and expired 13CO2 enrichment were determined by gas chromatograph mass spectrometry. Protein metabolism kinetics were calculated. Results were: nitrogen balance 0.27 +/- 0.01 g/kg/d, total protein flux 10.38 +/- 0.34 g/kg/d, total protein synthesis 9.64 +/- 0.31 g/kg/d, total protein breakdown 7.86 +/- 0.38 g/kg/d, and total protein oxidation/excretion 0.92 +/- 0.04 g/kg/d.(ABSTRACT TRUNCATED AT 250 WORDS)
Jones
M O
MO
Department of Paediatric Surgery, Alder Hey Children's Hospital, Liverpool, UK.
Pierro
A
A
Garlick
P J
PJ
McNurlan
M A
MA
Donnell
S C
SC
Lloyd
D A
DA
D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D002149:Energy Intake; D004734:Energy Metabolism / Q000502:physiology; D005217:Fat Emulsions, Intravenous; D005260:Female; D005947:Glucose / Q000008:administration & dosage*; D006801:Humans; D007231:Infant, Newborn / Q000378:metabolism*; D008297:Male; D009584:Nitrogen / Q000378:metabolism*; D010289:Parenteral Nutrition, Total; D011506:Proteins / Q000378:metabolism*
D004040:Dietary Carbohydrates; D005217:Fat Emulsions, Intravenous; D011506:Proteins; D005947:Glucose; D009584:Nitrogen