Parenteral amino acids increase albumin and skeletal muscle protein fractional synthetic rates in premature newborn minipigs.
OBJECTIVE
Early administration of parenteral amino acids increases whole body nitrogen retention in premature infants. Tracer kinetic studies suggest an increase in whole body protein synthesis as a possible mechanism for this increase in nitrogen retention. However, the effect of early parenteral amino acids on synthesis of specific proteins remains uncertain. Using premature newborn minipigs as a model for human premature newborns, we investigated the effects of parenterally administered amino acids on albumin and skeletal muscle protein fractional synthetic rates.


METHODS
Fifteen Yucatan minipigs were delivered by cesarean section 6 days before the mean expected delivery date (day 106 of gestation; expected gestation, 111-113 days) and randomized to two groups immediately after birth: 7 piglets received a mixture of amino acids (0.4 g. kg. h ) and glucose (0.8 g. kg. h ) for 5 hours, and 8 piglets (control group) received glucose only. All piglets received a continuous primed infusion of 1-[ C]valine. Arterial plasma free C-valine enrichment was measured by gas chromatography/mass spectrometry, and protein synthetic rates were determined by measuring incorporation of C-valine into albumin and skeletal muscle protein using gas chromatography/combustion/isotope ratio mass spectrometry.


RESULTS
Administration of amino acids increased albumin (87.0% +/- 42.1% [mean +/- SD] vs. 37.6% +/- 6.8% per 24 hours; < 0.05) and skeletal muscle fractional synthetic rates (11.60% +/- 6.9% vs. 6.5% +/- 1.5% per 24 hours; < 0.05).


CONCLUSIONS
We conclude that parenteral amino acids increase albumin and skeletal muscle fractional synthetic rates in premature piglets on the first day of life.
D000418:Albumins / Q000187:drug effects*; D000596:Amino Acids / Q000008:administration & dosage* / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn; D002247:Carbon Isotopes / Q000097:blood; D008401:Gas Chromatography-Mass Spectrometry; D005865:Gestational Age; D005947:Glucose / Q000494:pharmacology; D009124:Muscle Proteins / Q000096:biosynthesis* / Q000187:drug effects*; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism*; D010288:Parenteral Nutrition; D013552:Swine; D013997:Time Factors; D014633:Valine / Q000097:blood
D000418:Albumins; D000596:Amino Acids; D002247:Carbon Isotopes; D009124:Muscle Proteins; D014633:Valine; D005947:Glucose