Glutamine or Glutamine Dipeptide Supplementation Improves Gluconeogenesis and Liver Glycogenosis in Type 1 Diabetic Rats

The effects of the supplementation with L-glutamine (GLN) or L-alanyl-L-glutamine (GDP) on the progression of the systemic and hepatic metabolic status of rats having untreated type 1 diabetes mellitus (T1DM) were investigated. Male Wistar diabetic rats (streptozotocin, 60 mg/kg) were allotted to four groups supplemented by gavage for thirty days as follows: control and diabetic receiving saline; diabetic receiving GLN (248 mg/kg); and diabetic receiving GDP (400 mg/kg). Body weight, plasmatic parameters and kidney function were analyzed. Isolated hepatocytes were used to assess gluconeogenic capacity. Liver and kidney were used for morphological analyses. T1DM decreased the number and increased the area of the hepatocytes, possibly because of the observed enlargement of glycogen stores. Kidney weight, glomerular area and proteinuria increased, and glomerular filtration rate decreased, in non-supplemented T1DM rats. Glomerular area and proteinuria were reversed by both supplementations. The T1DM hepatocytes released less glucose, which could have been diverted to glycogen synthesis and secondary glycogenosis observed in T1DM; this was partially reversed by the supplementations. The results point to a possible beneficial effect of glutamine on the metabolic and hepatic impairments of T1DM.