Concerning the Relation of Environmental Temperature to Resistance to Thyroid and Thyroxine, and the Creatine Content of the Heart and Other Tissues in Experimental Hyperthyroidism

Abstract

In 1919 Stoland and Kinney (1) published a brief statement concerning the relation of external temperature to the toxicity of administered thyroid. They found that rats kept at 32°C. and receiving 0.2 gin. of desiccated thyroid daily, lived an average of 7.3 days; others at 25°C. lived an average of 22 days, while a third group kept at 180C. lived more than 32 days. A survey of the literature reveals no other reports specifically concerned with this question, although the more general problem of the relation of the environmental temperature to the structure and activity of the thyroid has been the subject of several investigations (2-9).The present work is partly the outgrowth of the observation by one of us (10) that rats are much more resistant to thyroid and thyroxine in cool than in warm weather. It is improbable that this simple and obvious relationship has not been frequently observed by experimental workers, and certainly in clinical practice; yet it is remarkable that even in the more authoritative and comprehensive discussions of the physiology, pharmacology and therapeutics of the thyroid hormone, little or no mention is made of the importance of environmental temperature in relation to its tolerance and toxicity. For this reason the present report seems to be justified. MethodsThe rats used in this work were from a pure inbred Wistar strain reared in the laboratory under very favorable conditions. Special attention was given to the

Effects of Thyroid on Creatine Metabolism With a Discussion of the Mechanism of Storage and Excretion of Creatine Bodies 1

“…Changes in the ability of the muscles to store or liberate creatine or phosphocreatine Analyses of muscles have shown that the concentration of creatine is decreased in thyrotoxicosis (4,26,27), in progressive muscular dystrophy (39,44) and in denervation atrophy (41 ). Wang (4) demonstrated increased creatine and phosphocreatine in the muscle of thyroidectomized rabbits, and Williamson and Gulick (42) The observations which we have recorded suggest that it has little, if any, influence.…”

“…Muscle creatine and phosphocreatine in hyperthyroidism and hypothyroidism In thyrotoxic rats a significant decrease of the creatine content of the striated muscle (26) and a decrease of both phosphocreatine and creatine in heart muscle (27) has been demonstrated. Wang (4), using improved methods, studied both creatine and phosphocreatine in rabbits.…”

Hypothermic Myxoedema Coma

“…There is experimental evidence that the maintenance of body temperature is thyroid‐dependent at low environmental temperatures (Bodansky et al 1936; Lancet 1956) and that there is increased activity of the thyroid gland in euthyroid animals exposed to cold (Bigelow and Sidlofsky 1961). Hypothyroid animals are less able to withstand exposure to cold (Leblond and Eartly 1952) and their body temperature falls more rapidly (Laties and Weiss 1959).…”