Effect of Morphine on Glucoregulatory Hormones (Insulin, Cortisol and Epinephrine) in Diabetic and Non-diabetic Mice

The role of morphine in blood glucose changes has been documented. The aim of the present study was to investigate the hormonal mechanisms involved in changes caused by morphine on blood glucose in diabetic and non-diabetic mice. Animals were divided into two, the diabetic and non-diabetic, groups. Each group was further divided into subgroups: 1. Saline+saline 2. Naloxone+morphine and 3. Control (saline+saline). Blood samples were used for determining the blood glucose as well as for hormonal (insulin, cortisol and epinephrine) analyses. In non-diabetic and diabetic mice, blood glucose was significantly decreased in the saline+morphine group, compared to controls at 3h and 1h respectively, a decrease which compensated in the naloxone+morphine group, compared to saline+morphine group. After 3h, the level of insulin in non-diabetic mice was significantly decreased compared to the controls and was compensated in the naloxone+morphine group. At this time, the level of insulin showed no changes in diabetic animals. The level of cortisol remained constant both in diabetic and non-diabetic animals at 3h. The level of epinephrine displayed a significant decrease in diabetic and non-diabetic mice at 3h when compared to the controls and was compensated in the naloxone+morphine compared to the saline+morphine group. The administration of subcutaneous morphine caused hypoglycemia in diabetic and non-diabetic mice. The hypoglycemia and the decrease of insulin level in non-diabetic mice as well as the unchanged level of this hormone in diabetic animals may suggest an insulin-independent hypoglycemia induced by morphine.