Effect of epinephrine infusions imitating plasma epinephrine levels in immobilization stress and of fasting on the activity of key enzymes of liver glycogen metabolism
Németh, S.; Viskupic, E.; Kvetnanský, R.; Kolena, J.
Physiologia Bohemoslovaca 36(6): 487-493
1987
ISSN/ISBN: 0369-9463 PMID: 2964044 Document Number: 289874
In adult male rats anaesthetized with pentobarbital, intravenous infusion of 0.25 microgram kg-1 min-1 of epinephrine increased plasma epinephrine levels to more than 10 pmol ml-1 within 5 min, the values remaining constant during the next 20 min. On the other hand, a maximal increase of liver phosphorylase a was found after 5 min and this response was attenuated at 10 and 20 minutes in the fed rats. Fasting for 24 h extinguished the greatest part of this response. During infusion, a decrease of liver synthase a activity was observed in the fasted and of total synthase activity in both the fed and fasted animals. In fed rats an i.v. bolus of 0.50 microgram.kg-1 or doubling of the infusion rate for 5 min, both immediately after 20 min of infusion, led to maximal phosphorylase a activity again and to a decrease of synthase a activity. The levels of cAMP in the liver were increased by the infusion in one series and unchanged in another.