Intrauterine growth restriction does not alter the response of
protein synthesis to feeding in newborn pigs.
Davis, Teresa A., Marta L. Fiorotto, Douglas G. Burrin, Wilson G.
Pond, and Hanh V. Nguyen.
USDA/ARS Children's Nutrition Research Center, Department of
Pediatrics, Baylor College of Medicine, Houston, Texas 77030
APStracts 4:0001E, 1997.
The study aimed to determine the effect of intrauterine growth
restriction (IUGR) on the acute response of tissue protein synthesis
to feeding in newborn pigs. Newborn pigs of sows fed either control
or protein-restricted diets throughout gestation were designated C or
IUGR, respectively. Both groups were either fasted for 9 h after
birth or fed hourly 30 mL colostrum/kg body wt for 2.75 h after a 6-h
fast. Fractional rates of tissue protein synthesis (KS) were measured
in vivo with a flooding dose of L-[4-3H]phenylalanine. Birth weight
was reduced by 33% in IUGR pigs. IUGR had no effect on KS in
skeletal muscles, heart, liver, jejunum, and pancreas. Feeding
stimulated tissue KS similarly in C and IUGR pigs. Fasting plasma
insulin concentrations and their rise with feeding were unaffected by
IUGR. Plasma insulin-like growth factor-I (IGF-I) concentrations were
reduced by 42% in IUGR pigs and were not altered by feeding in either
IUGR or C pigs. There were positive nonlinear relationships between
tissue KS and circulating concentrations of insulin. The results
indicate that, in newborn pigs, tissue fractional protein synthesis
rates are unaffected by IUGR, despite reduced plasma IGF-I
concentrations. The efficiency with which nutrients stimulate tissue
fractional protein synthesis rates is also not altered by IUGR,
perhaps because the rise in plasma insulin concentrations with
feeding is unaffected by IUGR.
Received 19 August 1996; accepted in final form 20 December 1996.
APS Manuscript Number E410-6.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1997 The American Physiological Society.
Published in APStracts on 21 January 1997