Effect of oleanolic acid on small intestine morphology and enzymes of glutamine metabolism in diabetic rats.

The small intestine (SI) is the main site for food absorption and glutamine utilization hence critical in metabolic disorders that involve energy balance such as diabetes. This study investigates the effects of oleanolic acid (OA) on SI morphology and some enzymes of glutamine metabolism in male Sprague-Dawley diabetic rats. High dose STZ-induced diabetes (HDD) and low dose STZ-induced diabetes (LDD) were induced by intraperitoneal injection of 60 and 40 mg streptozotocin/kg body weight respectively. Non-diabetic and diabetic rats were treated for two weeks with OA, insulin or OA + insulin in HDD study while animals in the in LDD study were treated with OA. There was significant (P<0.05) increase in the weight of the SI of diabetic animals and of villus height (VH) in the jejunum and duodenum of HDD animals. OA and insulin treatment significantly decreased VH in duodenum of HDD animals while OA treatment profoundly increased VH in normal rats. Jejunal of phosphate-dependent glutaminase (PDG) activity was unaffected by diabetes however alanine aminotransferase, aspartate aminotransferase and glutamate dehydrogenase activities were significantly (P<0.05) elevated by diabetes and treatments decreased these elevated aminotransferase activities. It is suggested that the intestine meets the energy demand in diabetes by modulating the activities of aminotransferases without change in PDG activity.