[Action of thyroid hormones on the calorigenic effect of adrenaline]

The present investigation was undertaken in order to appraise the interaction between thyroxine and epinephrine in dogs exposed to acute cold. In normal, then successively thyroidectomized, adrenal demedullated and thyroxine restored dogs, epinephrine was infused in basal condition and during acute cold exposure. In thyroidectomized dogs epinephrine lost its calorigenic effects. So it did in thyroidectomized and adrenal demedullated dogs. Conversely, when dogs were restored in thyroxine, epinephrine recovered its calorigenic effect. Evidence for thyroxine-catecholamine interaction can be seen in basal condition as during acute cold. Nevertheless, this interaction is more obvious during shivering thermogenesis.