Effect Of Intrathecal Morphine on Blood Glucose, Glucagon and Tissue Glycogen in Rat, Comparison with The Effect of Xanthan Gum on Blood Glucose

The effects of intrathecal (i. t.) morphine (25-100 g) and of the intraperitoneal (i. p.) xanthan gum (30 and 60 mg/kg) on blood glucose level were studied in non- fasted rats. Morphine produced a time and dose-dependent hypoglycemia, whereas xanthan caused a moderately decreasing effect on blood glucose. Morphine and xanthan appear to be acting by different mechanisms, although the hypoglycemic effects of morphine appear to be due largely to an increased glucose uptake by skeletal muscle. Xanthan has a slow onset of hypoglycemic action which may allow homeostatic mechanisms to intervene. On the other hand, glucagon was increased significantly after i. t. morphine (50 g) both at 30 and 60 min. The hyperglucagonaemic response after morphine may be due to a direct opioid effect on pancreas. The i. t. administration of morphine (50 g) caused a time-dependent decrease in liver and muscle glycogen levels in morphine-treated rats compared with saline-controlled rats. The data obtained in the present work point to active utilization of liver and muscle glycogen (glycogenolysis) in morphinised animals concomitant with hypoglycemia and increased glucagon levels.