Glucose transport in the equine hoof

Asplin, K. E., Curlewis, J. D., McGowan, C. M., Pollitt, C. C. and Sillence, M. N. (2011) Glucose transport in the equine hoof. Equine Veterinary Journal, 43 2: 196-201. doi:10.1111/j.2042-3306.2010.00127.x


Author Asplin, K. E.
Curlewis, J. D.
McGowan, C. M.
Pollitt, C. C.
Sillence, M. N.
Title Glucose transport in the equine hoof
Journal name Equine Veterinary Journal   Check publisher's open access policy
ISSN 0425-1644
2042-3306
Publication date 2011-03
Year available 2010
Sub-type Article (original research)
DOI 10.1111/j.2042-3306.2010.00127.x
Volume 43
Issue 2
Start page 196
End page 201
Total pages 6
Place of publication Hoboken, NJ, United States
Publisher John Wiley & Sons
Collection year 2012
Language eng
Formatted abstract
Reasons for performing study: Several conditions associated with laminitis in horses are also associated with insulin resistance, which represents the failure of glucose uptake via the insulin-responsive glucose transport proteins in certain tissues. Glucose starvation is a possible mechanism of laminitis, but glucose uptake mechanisms in the hoof are not well understood.

Objectives
: To determine whether glucose uptake in equine lamellae is dependent on insulin, to characterise the glucose transport mechanism in lamellae from healthy horses and ponies, and to compare this with ponies with laminitis.

Methods:Study 1 investigated the effects of insulin (300 µU/ml; acute and 24 h) and various concentrations of glucose up to 24 mmol/l, on 2-deoxy-D-[2,6-3H]glucose uptake in hoof lamellar explants in vitro. Study 2 measured the mRNA expression of GLUT1 and GLUT4 transport proteins by PCR analysis in coronary band and lamellar tissue from healthy horses and ponies, ponies with insulin-induced laminitis, and ponies suffering from chronic laminitis as a result of equine Cushing's syndrome.

Results: Glucose uptake was not affected by insulin. Furthermore, the relationship between glucose concentration and glucose uptake was consistent with an insulin-independent glucose transport system. GLUT1 mRNA expression was strong in brain, coronary band and lamellar tissue, but was weak in skeletal muscle. Expression of GLUT4 mRNA was strong in skeletal muscle, but was either absent or barely detectable in coronary band and lamellar tissue.

Conclusions: The results do not support a glucose deprivation model for laminitis, in which glucose uptake in the hoof is impaired by reduced insulin sensitivity. Hoof lamellae rely on a GLUT1-mediated glucose transport system, and it is unlikely that GLUT4 proteins play a substantial role in this tissue.

Potential relevance: Laminitis associated with insulin resistance is unlikely to be due to impaired glucose uptake and subsequent glucose deprivation in lamellae.
Keyword Horse
Laminitis
Glucose
Insulin
Glut
Insulin resistance
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Issue published online: 24 FEB 2011 Article first published online: 5 JUL 2010

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2012 Collection
School of Biomedical Sciences Publications
School of Veterinary Science Publications
 
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