Epinephrine as a metabolic regulatory hormone in irradiated rats

ABSTRACT

The role of epinephrine as a regulatory hormone was examined in normal and irradiated rats. Epinephrine was intraperitoneally injected into rats at a concentration of 200 microg/kg body weight. Epinephrine was injected either 15 minutes before or just after whole body gamma irradiation 6 Gy [single dose]. The variations in serum epinephrine, norepinephrine, triglycerides, lipase activity, glucose and lactic acid were selected as biochemical markers in this study. Biochemical estimations were undertaken at 1 hr, 4 hrs, 1, 3 and 7 days after treatment [after irradiation]. The data obtained revealed that the treatment of normal rats with epinephrine induced a significant increase in serum epinephrine level 1 hr after injection, while the level of norepinephrine significantly increased at 4 hrs. Lipase activity significantly increased on the 1[st] hr post treatment. A significant decrease in the level of triglycerides was recorded 1 and 4 hrs post treatment. Serum glucose significantly increased at 1 and 4 hrs post treatment, while no significant changes were recorded for lactic acid. In gamma irradiated rats, the level of serum epinephrine significantly decreased at 1 hr followed by significant increases recorded at 1, 3, and 7 days after irradiation. Norepinephrine levels significantly decreased after irradiation during all the experimental time periods. The levels of triglycerides show significant increases accompanied by a decrease in lipase activity. A temporary decrease of glucose level was recorded at 1 hr followed by significant increase recorded at 1, 3, and 7 days post irradiation. Lactic acid levels show significant increase during all the experimental time periods. The data revealed that treatment of rats, with epinephrine, either pre or post irradiation, has diminished the radiation induced changes in most of the studied parameters. Accordingly, it could be concluded that epinephrine could exert a beneficial protective role against certain radiation induced disorders through acting as a regulatory hormone of the metabolic pathways