Effects of prolonged glucagon administration to turtles ( Chrysemys d'Orbignyi)

Abstract

Studies have been conducted on the action of glucagon upon carbohydrate metabolism of turtles ( Chrysemys d'orbignyi) during summer or winter. Daily administration of glucagon (100 μg/kg) for 30 days produced intense hyperglycemia, this effect being greater during winter than in summer. Also, the effect in winter decreased as the experiment proceeded. Blood glucose reached normal levels 20 days after suspension of glucagon treatment. At the end of experiment, the liver glycogen concentration of the treated turtles was lower than in the controls. Muscle glycogen values were not changed by glucagon injections. Plasma insulin-like activity from the treated animals was increased. Pancreas insulin content from the treated animals did not present appreciable modification during the summer, but it was reduced in experiments performed during the winter.