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


OBJECTIVE
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.
Litten
J C
JC
Department of Agriculture, University of Reading, Reading, UK. j.c.litten@rdg.ac.uk
Mostyn
A
A
Laws
J
J
Corson
A M
AM
Symonds
M E
ME
Clarke
L
L
D020155:3-Hydroxybutyric Acid / Q000097:blood; D000818:Animals; D000831:Animals, Newborn; D001786:Blood Glucose / Q000378:metabolism; D001823:Body Composition / Q000187:drug effects / Q000502:physiology; D001833:Body Temperature Regulation / Q000187:drug effects* / Q000502:physiology; D001835:Body Weight / Q000187:drug effects / Q000502:physiology; D004703:Endocrine System / Q000187:drug effects*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D007328:Insulin / Q000097:blood; D007473:Ion Channels / Q000097:blood / Q000235:genetics; D007773:Lactates / Q000097:blood; D020738:Leptin / Q000097:blood / Q000235:genetics / Q000494:pharmacology*; D008297:Male; D024101:Mitochondrial Proteins / Q000097:blood / Q000235:genetics; D012313:RNA / Q000737:chemistry / Q000235:genetics; D011897:Random Allocation; D011994:Recombinant Proteins / Q000097:blood / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D013552:Swine / Q000097:blood / Q000502:physiology*; D013974:Thyroxine / Q000097:blood; D014280:Triglycerides / Q000097:blood; D014284:Triiodothyronine / Q000097:blood; D000071246:Uncoupling Protein 2
D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D007473:Ion Channels; D007773:Lactates; D020738:Leptin; D024101:Mitochondrial Proteins; D011994:Recombinant Proteins; D014280:Triglycerides; C000604389:UCP2 protein, human; D000071246:Uncoupling Protein 2; D014284:Triiodothyronine; D012313:RNA; D013974:Thyroxine; D020155:3-Hydroxybutyric Acid