Hibernation of the Thirteen-Lined Ground Squirrel, Citellus tridecemlineatus (Mitchill). IV. Influence of Thyroxin, Pituitrin and Desiccated Thymus and Thyroid on Hibernation

Abstract

The feeding of desiccated thymus and thyroid in large doses to 27 and 23 animals, respectively, resulted in no definite increase or decrease in tendency of ground squirrels to hibernate when subjected to cold temp. The injection of thyroxin and pituitrin in doses which were, respectively, 225 and 450 times the human dose on the basis of relative weights, produced no change in tendency to hibernate in 66 and 116 animals, respectively, in comparison with the same number of controls. The animals were subjected to cold after the injections. The experiments indicate that the secretions of the thymus, thyroid and posterior pituitary are not important agents in the production or prevention of hibernation.