Effects of an intravenous endotoxin challenge on glucose and insulin dynamics in horses.
OBJECTIVE
To evaluate the effects of endotoxin administered IV on glucose and insulin dynamics in horses.


METHODS
16 healthy adult mares.


METHODS
Each week of a 2-week randomized crossover study, each horse received an IV injection (duration, 30 minutes) of Escherichia coli O55:B5 lipopolysaccharide (LPS) in 60 mL of sterile saline (0.9% NaCl) solution (20 ng/kg) or sterile saline solution alone (control treatment). Frequently sampled IV glucose tolerance test procedures were performed at 24 hours before (baseline) and 24 and 48 hours after injection; glucose and insulin dynamics were assessed via minimal model analysis.


RESULTS
13 of 16 horses had a clinical response to LPS, which was characterized by mild colic and leukopenia. Before treatment, mean +/- SD insulin sensitivity was 2.9 +/- 1.9 x 10(4) L x min(1) x mU(1); this significantly decreased to 0.9 +/- 0.9 x 10(4) L x min(1) x mU(1) 24 hours after treatment (69% reduction) and was 1.5 +/- 0.9 x 10(4) L x min(1) x mU(1) 48 hours after treatment. At baseline, mean +/- SD acute insulin response to glucose was 520 +/- 196 mU x min x L(1); this significantly increased to 938 +/- 620 mU x min x L(1) (80% increase) and 755 +/- 400 mU x min x L(1) (45% increase) at 24 and 48 hours after LPS treatment, respectively.


CONCLUSIONS
Compared with baseline values, insulin sensitivity was decreased for 24 hours after IV injection of LPS, and affected horses had a compensatory pancreatic response. These disturbances in glucose and insulin dynamics may contribute to development of laminitis in horses.
Tóth
Ferenc
F
Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996, USA.
Frank
Nicholas
N
Elliott
Sarah B
SB
Geor
Raymond J
RJ
Boston
Raymond C
RC
D000818:Animals; D001786:Blood Glucose / Q000187:drug effects* / Q000378:metabolism; D018592:Cross-Over Studies; D005260:Female; D006736:Horses / Q000097:blood / Q000378:metabolism*; D007328:Insulin / Q000097:blood / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000009:adverse effects*
D001786:Blood Glucose; D007328:Insulin; D008070:Lipopolysaccharides