title: Effects of early postnatal growth restriction and subsequent catch-up growth on body composition, insulin sensitivity, and behavior in neonatal rats.
abstract: BACKGROUND
  Early postnatal growth retardation with subsequent catch-up growth is common in preterm infants. We describe a model of ex utero (postnatal) growth retardation followed by varying degrees of catch-up growth in the neonatal rat.
  
  
  METHODS
  Newborn CD rat pups were randomized to litters of 10 (NN, normal then normal intake) or 16 (R, restricted intake). On day 10, R pups were further randomized to litters of 6 (RC, restricted then catch-up intake), 10 (RN, restricted then normal intake), or 16 (RR, restricted then restricted intake). Body weight, body composition, insulin sensitivity, biochemistry, and learning (passive avoidance test) were assessed.
  
  
  RESULTS
  Growth was significantly lower in the R than the NN group. Subsequently, the RC group caught up with the NN group but had higher fat mass; the RN group showed partial catch-up but body composition similar to that of the NN group. Insulin sensitivity did not differ between groups. Learning behavior was significantly better in the NN than the three R groups, and in the RC group than the RR or RN groups.
  
  
  CONCLUSIONS
  Early postnatal growth retardation is associated with poorer medium-term growth and poorer developmental outcome. Increased catch-up growth is associated with improved developmental outcome but with increased body adiposity, without any significant effect on glucose homeostasis.
authors: Department of Nutrition, University of California-Davis, Davis, California, USA.
authors: Ming-Yu
authors: MY
authors: Jou
authors: Bo
authors: B
authors: Lönnerdal
authors: Ian J
authors: IJ
authors: Griffin
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001522:Behavior, Animal; D001823:Body Composition; D005260:Female; D006128:Growth; D007333:Insulin Resistance; D008297:Male; D051381:Rats