Morris Animal Foundation Study Sponsored by ARF

Arginine Stimulation Testing—Development of a Quantitative Method of Assessing Insulin Sensitivity in Camelids

Principal investigator:

Anna Firshman, BVSc, PhD
Oregon State University College of Veterinary Medicine

Hospitalized llamas and alpacas (camelids) often develop a condition known as fatty liver, which, regardless of the severity of the initial problem, often causes death. Their susceptibility to this condition may be due in part to their unique way of handling blood sugar. Previous studies have shown that camelids have reduced glucose tolerance and sensitivity to insulin compared with other species. Researchers successfully evaluated insulin secretion and sensitivity in these animals using special techniques, called hyperglycemic and hyperinsulinemic euglycemic clamping, that are known to provide the most accurate indicators of glucose metabolism and insulin secretion in other animals and humans. They learned that the camelid pancreas has a reduced capacity to excrete insulin, and this insufficiency is likely responsible for the hyperglycemia often seen in camelids. They also found that once insulin stimulates a camelid's body tissues fully, the tissues can take up glucose at a similar rate as other species. These findings provide insight into why camelids are susceptible to disorders of negative energy balance, such as fatty liver, and will help scientists develop effective treatment strategies.