Effects of acute endotoxemia on serum somatotropin and insulin-like growth factor I concentrations in prepubertal gilts.
OBJECTIVE
To evaluate effects of endotoxemia on serum somatotropin (ST) and insulin-like growth factor I (IGF-I) concentrations in finishing pigs.


METHODS
Eight female pigs (98 +/- 2 kg) randomly assigned to IV administration (time 0) of saline solution (n = 4) or Escherichia coli lipopolysaccharide (LPS; 5 micrograms/kg of body weight; n = 4).


METHODS
Serum ST concentration was determined in serum samples obtained at 20-minute intervals for 6 hours after treatment. Serum IGF-I concentration was determined in samples collected at 1-hour intervals for 6 hours and at 12, 15, 18, 24, 48, 72, and 96 hours after treatment.


RESULTS
One distinct pulse of ST (peak 10.5 +/- 0.5 ng/ml) was observed at 40 minutes in each pig after administration of LPS. Control pigs had 2.25 +/- 0.48 ST pulses during the 6 hours of frequent sample collection; however, magnitude of the ST pulses was similar between gilts given LPS and control gilts. A temporal association between ST pulses and saline administration was not evident. Serum IGF-I concentration was similar between gilts of the LPS and control groups prior to treatment. The IGF-I concentration was similar between gilts of the LPS and control groups prior to treatment. The IGF-I concentration was lower (P < 0.01) in gilts of the LPS group (44 +/- 5 ng/ml) than in gilts of the control group (157 +/- 4 ng/ml) at 24 hours. The difference in IGF-I concentrations between groups was evident for 96 hours.


CONCLUSIONS
Immediate release of ST was attributed to stress associated with acute endotoxemia and stimulation of the pituitary gland; immune stimulation by LPS may have contributed to the changes in IGF-I concentration. Because feed consumption was similar between the 2 groups of pigs, suppression of IGF-I concentration for 96 hours after administration of LPS was attributable to factors in addition to transient feed restriction. Thus, acute endotoxemia altered the positive association between ST and IGF-I, and provided evidence for a potential mechanism of impaired growth in endotoxemic animals.
Hevener
W
W
Department of Food Animal & Equine Medicine, North Carolina State University, Raleigh 27606, USA.
Almond
G W
GW
Armstrong
J D
JD
Richards
R G
RG
D000818:Animals; D019446:Endotoxemia / Q000097:blood*; D004926:Escherichia coli; D005260:Female; D013006:Growth Hormone / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000032:analysis / Q000378:metabolism*; D007700:Kinetics; D008070:Lipopolysaccharides; D012741:Sexual Maturation; D013552:Swine; D013997:Time Factors
D008070:Lipopolysaccharides; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone