Effect of Acute Administration of Recombinant Human Leptin during the Neonatal Period on Body Temperature and Endocrine Profile of the Piglet

Neonatology. 2008;93(3):171-7. doi: 10.1159/000108926. Epub 2007 Sep 24.

Abstract

Background: Leptin is produced predominantly by white adipocytes; in adults it regulates appetite and energy expenditure but its role in the neonate remains to be fully established.

Objectives: To examine the effects of acute administration of recombinant human leptin on the endocrine profile and thermoregulation of neonatal pigs.

Methods: 24 pairs of siblings (n = 48) were administered with either a single dose (4 microg ml(-1) kg(-1) body weight) of leptin (L: n = 24) or a placebo (P: n = 24) on day 6 of neonatal life. Rectal temperature was recorded, and tissue samples were taken at 1 (n = 12), 2 (n = 12), 4 (n = 12) or 6 (n = 12) hours post-administration. Plasma concentrations of hormones and metabolites were determined in conjunction with messenger RNA (mRNA) for leptin and uncoupling protein-2.

Results: Plasma leptin increased following leptin administration, and differences in concentrations of insulin, thyroxine and non-esterified fatty acids were observed between the two groups. Initially, rectal temperature decreased in L pigs but returned to start values by 1.5 h. This decline in rectal temperature was delayed in placebo animals, resulting in differences between treatments at 1.5 and 2 h.

Conclusions: Acute leptin administration alters the endocrine profile of pigs and influences the thermoregulatory ability of the neonate.

MeSH terms

  • 3-Hydroxybutyric Acid / blood
  • Animals
  • Animals, Newborn
  • Blood Glucose / metabolism
  • Body Composition / drug effects
  • Body Composition / physiology
  • Body Temperature Regulation / drug effects*
  • Body Temperature Regulation / physiology
  • Body Weight / drug effects
  • Body Weight / physiology
  • Endocrine System / drug effects*
  • Fatty Acids, Nonesterified / blood
  • Female
  • Insulin / blood
  • Ion Channels / blood
  • Ion Channels / genetics
  • Lactates / blood
  • Leptin / blood
  • Leptin / genetics
  • Leptin / pharmacology*
  • Male
  • Mitochondrial Proteins / blood
  • Mitochondrial Proteins / genetics
  • RNA / chemistry
  • RNA / genetics
  • Random Allocation
  • Recombinant Proteins / blood
  • Recombinant Proteins / pharmacology
  • Reverse Transcriptase Polymerase Chain Reaction / veterinary
  • Swine / blood
  • Swine / physiology*
  • Thyroxine / blood
  • Triglycerides / blood
  • Triiodothyronine / blood
  • Uncoupling Protein 2

Substances

  • Blood Glucose
  • Fatty Acids, Nonesterified
  • Insulin
  • Ion Channels
  • Lactates
  • Leptin
  • Mitochondrial Proteins
  • Recombinant Proteins
  • Triglycerides
  • UCP2 protein, human
  • Uncoupling Protein 2
  • Triiodothyronine
  • RNA
  • Thyroxine
  • 3-Hydroxybutyric Acid