EFFECTS OF THYROXINE ON GLYCOGEN STORES AND OXYGEN CONSUMPTION IN LEOPARD FROG RANA PIPIENS

The effects of thyroxine treatment on tissue glycogen content and oxygen consumption of adult Rana pipiens were investigated at 18 and 30°C. At 18°C, (1) thyroxine treatment significantly decreased muscle glycogen (-37%), and increased (+32%) liver glycogen at 16 days; (2) oxygen consumption of thyroxine-treated frogs rose 10%, while that of sham-injected frogs decreased by 17%, from initial values, by the third week. At 30°C, (1) thyroxine treatment significantly decreased (-42%) muscle glycogen from sham levels, by 16 days; liver glycogen was unchanged; (2) thyroxine treatment rapidly increased oxygen consumption (+33% by 15 days) to values significantly higher than those for sham-injected frogs. Cessation of thyroxine injections for 3 days allowed oxygen consumption to fall to control levels. © 1969.