Effects of exogenous insulin on glucose tolerance in alpacas

Objective-To evaluate the effects of exogenous insulin on clearance of exog enous glucose in alpacas. Animals-7 adult castrated male alpacas. Procedure-Prior to each of 2 trials, food was withheld for 8 hours. Glucose (0.5 g/kg of body weight) was then administered by rapid IV infusion. Duri ng 1 of the trials, regular insulin (0.2 U/kg, IV) was also administered 15 minutes later. Blood was collected immediately before (0 minutes) and 15, 20, 25, 30, 45, 60, 90, 120, 180, and 240 minutes after glucose administrat ion. Plasma concentrations of glucose and lactate were determined, and gluc ose fractional turnover rate and plasma half-life were calculated. Results-Insulin treatment caused a significant increase in fractional turno ver rate of glucose and plasma lactate concentration. Plasma glucose concen trations were less in insulin-treated alpacas from 30 minutes after glucose administration (15 minutes after insulin administration) until the conclus ion of each trial, compared with nontreated alpacas. In addition, plasma gl ucose concentration in insulin-treated alpacas returned to baseline values 1 hour sooner than in the nontreated group. Conclusions and Clinical Relevance-Glucose uptake in alpacas improves after insulin treatment, suggesting that administration of exogenous insulin wil l increase the therapeutic and decrease the pathologic effects of exogenous glucose administered to hypoglycemic alpacas. However, alpacas and other N ew World camelids should be monitored carefully during treatment with gluco se or insulin, because these species appear to be partially insulin resista nt.