Blood glucose and insulin concentrations after alpha‐2‐agonists administration in horses with and without insulin dysregulation

Abstract

Background In metabolically stable horses, alpha‐2‐agonists suppress insulin secretion with transient hyperglycemia and rebound hyperinsulinemia. In horses with insulin dysregulation (ID), the effect of alpha‐2‐agonists has not been investigated; however, both the alpha‐2‐agonist‐induced suppression of insulin secretion and rebound hyperinsulinemia could have clinical relevance. Hypothesis/Objectives In horses with ID, alpha‐2‐agonists will alter insulin and glucose dynamics. Animals Seven horses with ID and 7 control horses. Methods In this randomized crossover study, xylazine hydrochloride (1.1 mg/kg) or detomidine hydrochloride (30 μg/kg) were administered IV, and blood was collected for glucose and insulin concentrations at 0, 15, 30, 45, 60, 90, 120, 150, 180, and 300 minutes after administration. Horses received each drug in a random order with a 24‐hour washout period between drugs. Percent change in glucose and insulin concentrations was compared between groups, drugs, and over time with P < .05 considered significant. Results A significant time‐dependent effect of both alpha‐2‐agonists on glucose and insulin concentrations in control and ID horses was identified (P = .01 for all comparisons). There was no significant effect of sedative selection and endocrine status on blood glucose concentration in either group; however, in ID horses, xylazine administration resulted in severe rebound hyperinsulinemia whereas detomidine administration did not (P = .02). Conclusions and Clinical Importance Alpha‐2‐agonists have a significant effect on glucose and insulin concentrations in horses. In ID horses, detomidine could minimize hyperinsulinemia when compared to xylazine.

Changes Associated with the Peri-Ovulatory Period, Age and Pregnancy in ACTH, Cortisol, Glucose and Insulin Concentrations in Mares

“…Equine ID is described as a complex metabolic disorder, consisting of both peripheral tissue insulin resistance and hyperinsulinemia (basal or post-prandial), with hyperinsulinemia being associated with laminitis development [ 10 ]. Similar to that which has been described for PPID, previous studies have demonstrated how insulin sensitivity varies with environmental and pathological factors, such as seasonal changes, stress, age, genetics, diet, obesity and systemic disease, but limited data are available regarding the physiological role of internal factors [ 11 , 12 , 13 , 14 , 15 ].…”

Suspected vagal reflex and hyperkalaemia inducing asystole in an anaesthetised horse

“…Both hyperglycaemia and insulin deficiency can cause hyperkalaemia by cellular water loss and decreased cellular uptake of potassium, respectively, 22 which has been documented in human medicine 39 . Xylazine as both a bolus and continuous rate infusion as used in the case presented causes hyperglycaemia in horses, 40‐42 however, these studies did not document concurrent hyperkalaemia. Perioperative hyperglycaemia was documented in the present case, and further glucose was administered after asystole as an emergency treatment for hyperkalaemia alongside insulin, which may or may not have been the correct approach given the hyperglycaemia.…”

“…The lungs of the horse were ventilated throughout the anaesthetic (HorseVent; 6-8 bpm; tidal volume 15 ml/kg; peak inspiratory pressure 22-30 cmH 2 O; positive end-expiratory pressure 3-5 cmH 2 O; to maintain normocapnia [EtCO 2 [35][36][37][38][39][40][41][42][43][44][45]). Continuous rate infusions (CRIs) of ketamine (1.2 mg/kg/h), midazolam (0.02 mg/ kg/h) and xylazine (0.3 mg/kg/h) were infused IV combined as a triple drip in one CRI as per the hospital protocol.…”

Evaluation of the combined glucose‐insulin and intravenous glucose tolerance tests for insulin dysregulation diagnosis in donkeys

“…It has been shown in horses that season (β-cell sensitivity), circadian rhythm, diet (structural carbohydrate content), fasting, stress, α 2 -adrenergic agonists and pregnancy could influence endocrine variable and response to dynamic tests. 28,30,38,[40][41][42] Since all baseline samples for the inclusion criteria were collected in the morning in early July, all dynamic tests were performed in the last 2 weeks of July, all animals were kept in the same facility under a feeding protocol similar to the farm of origin, stress was reduced and no treatments were administered; these factors could be discarded.…”