بررسي اثر عصاره آبي - الكلي گياه كلپوره Teucrium polium بر ترشح انسولين از جزاير لانگرهانس جدا شده موش صحرايي

Evaluation of the Effect of Aqueous - Alcoholic Extract of Teucrium Polium on Insulin Secretion from Isolated Rat Pancreatic Islets

Background and Objective: Teucrium Polium (Labiatae) grows widespread in Iran and reduces blood sugar in-vivo. To examine the mechanism of this effect, in this study we explored the effects of aqueous-alcoholic extract of this plant on insulin secretion of isolated rat pancreatic islets. Materials and Methods: In this experimental study, the upper parts of the plant (stem, flowers and leaves) have been ground and extracted by incubating in 500ml of 50% alcohol at 40 °C for 72 hours. Then the solvent was evaporated in vacuum and reconstituted in DMSO which diluted with Krebʹs solution, rats were anesthetized with thiopental, for isolation of Islets, in each experiment. The pancreases were isolated and digested with collagenase and isolated islets were collected manually under a stereomicroscope. Isolated islets were pre-incubated in Krebʹs buffer with 3mM for 30min and then incubated with glucose 3mM or l0mM) with or without Isobutyl-Methylxanthine (IBMX) or the extract (0.1% and 1%) for one hour. Results: Our results showed that l0mM glucose stimulated insulin secretion. IBMX augmented glucose-induced insulin release (GIIR) in a dose-dependent manner. However, the extract, in concentration of 0.1%, did not change GIIR and in a concentration of 1% significantly decreased GIIR. Conclusion: Teucrium Polium extract has not insulinotropic property. The mechanism of inhibitory effect of the extract in the concentration of 1% is not clear and is may be due to the toxicity which the extract produces in high concentrations. We may conclude that the in-vivo hypoglycemic effect of is probably the result of changing the rate of glucose metabolism or increasing the sensitivity of peripheral tissue to insulin.