Discussion

Keen, J., Stratford, C., Lyle, C.
Aims: To evaluate the CGIT in endocrinopathic laminitis and determine whether it is more useful than resting indices of glucose and insulin for monitoring response to treatments. Methods: CGITs were carried out on cases referred for evaluation of chronic laminitis (in remission) to the DVEH, R(D)SVS. Cases were defined as pituitary pars intermedia dysfunction (PPID; n = 7) or equine metabolic syndrome (EMS; n = 6) based on clinical, resting and dynamic endocrine evaluation. Two nonobese controls with no history or signs of laminitis were also evaluated. Seven cases were followed- up over a period of 2 - 8 months. Results: Resting glucose and insulin were not significantly different between EMS and PPID groups. All cases had an abnormal CGIT curve except one case of PPID. Two controls had a 'normal' CGIT despite being non- Thoroughbreds and phenotypically obese. When grouped according to diagnosis, glucose concentration at 45 min (G45) was significantly increased in EMS compared to PPID. Insulin concentrations at 45 min (I45) reached the assay threshold in most cases, so was not significantly different between the PPID and EMS groups. The 2 controls, despite resting values within the normal reference range, had exaggerated insulin response according to the study of Eiler et al. (2005) (171 and 191 miu/l). Resting glucose and insulin values were not significantly affected by treatment. The CGIT improved in all individual cases following treatment. When grouped according to diagnosis and as a whole (i.e. all endocrinopathic laminitis cases), the area under the curve was reduced following treatment. There was no change in G45 but a significant reduction in I45 when all cases were grouped. Conclusions and practical significance: The CGIT may be useful for monitoring the treatment response in endocrinopathic laminitis, whatever the diagnosis, offering more information than resting glucose and insulin values alone. Acknowledgement: Colleagues at the DVEH, R(D)SVS.