Postprandial Changes in Plasma Free Amino Acids in Weanling Horses

s / Journal of Equine Veterinary Science 31 (2011) 230-356 328 (PROC MIXED) of SAS (SAS Institute Inc.) with horse as random. Differences were considered at P .05. Results and Discussion: Compared to control horses, mRNA abundance of IR and GLUT4 was lower (P .01) in the SIM of PPID horses. For GLUT1, GLUT2, GLUT5 and SGLT1, mRNA abundance did not differ between PPID and control horses. For SGLT1, GLUT2, GLUT1 and GLUT5 and, mRNA abundance did not differ between PPID and control horses. Protein expression of GLUT-4 was confirmed in all horses tested by visualization of a single band on Western blot, changing in relative abundance with the amount of protein loaded. Immunohistochemical staining revealed abundant labeling of GLUT4 in the epithelium and the muscularis mucosa and was confirmed in muscle tissue. Others have also reported GLUT4 transcript, albeit in low abundance, in small intestinal mucosa of the pig [5]. Results indicate that PPID down-regulates the expression of insulin-dependent glucose transporter GLUT4 and IR at the transcription level in the proximal jejunum of the horse. Thus far, dysfunctional glucose uptake into muscle and fat cells has been shown to contribute to the onset of type II diabetes, but little attention has been given to the role of the intestine in the pathology of the condition. In equine species, it is possible that intestinal GLUT4 plays a critical in controlling post-prandial blood glucose clearance. Conclusion: Horses with PPID had lower mRNA abundance of genes encoding for insulin-dependent glucose transporter GLUT4 and IR compared to non-PPID horses. These results shed light on the physiological mechanisms for increased susceptibility to nutritionally induced laminitis in PPID-afflicted horses.