Insulin Resistance in Horses
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202 – March/April, 2018
BY HEATHER SMITH THOMAS
Some horses are easy keepers. If they are overfed, some of these horses tend to develop insulin resistance. Owners need to be careful what and how they feed these individuals to avoid problems like laminitis. Insulin resistance problems are generally lumped into what has been termed Equine Metabolic Syndrome.
Dr. Shannon Pratt Phillips, Department of Animal Science, North Carolina State University says insulin resistance is defined as an inability of insulin to exert its effects on target tissue—such as adipose tissue or glucose. “Normally, insulin is released from the pancreas in response to increases of blood glucose concentration which would occur following a meal that contains starch or sugar,” she explains.
“When glucose concentrations go up, insulin is released from the pancreas. What the insulin does is work through receptors on cells of these tissues to ‘open the door’ and allow glucose to leave the bloodstream and go into those tissues. Because the glucose is leaving the bloodstream to go into the tissues, the blood glucose concentration goes down and then insulin concentrations go down as well,” she says.
“If the horse has insulin resistance however, the insulin cannot open that door and the glucose does not go into the cells. The mechanism regarding why that happens is still not entirely understood. It’s a complex process,” says Phillips.
“Normally, insulin will bind to a receptor and that sets off multiple reactions within the cell that ultimately makes these transporters (the little doors) for glucose move from sitting inside the cell to the cell surface membrane so the glucose can go in. Somewhere along that route, in the insulin-resistant horse, the insulin is not functioning properly. The result (because glucose cannot leave the blood as easily) is that the glucose stays in the blood. If the blood glucose concentrations stay high, this means that more insulin will be released from the pancreas to try to deal with the glucose. So this results in more and more insulin released,” she says.
Click here to read the complete article202 – March/April, 2018
