Thyroid Therapy in Cretix Sheep 



197 



96 (2056) 



Effects of thyroxin, thyroid extract, and sodium iodide, respec- 

 tively, on neuro-muscular activity in cretin sheep. 



By HOWARD S. LIDDELL and SUTHERLAND SIMPSON. 



[From the Department of Physiology and Biochemistry, Cornell 

 University Medical College, Ithaca, X. Y.] 



Thyroxin was administered to four cretin sheep in the form 

 of daily subcutaneous injections and its influence on the sponta- 

 neous activity of the animals was estimated by means of a pedo- 

 meter attached to the fore leg. One cretin had been thyroid- 

 ectomized at about six weeks of age and showed extreme mus- 

 cular weakness four months later. Daily subcutaneous injec- 

 tions of one half milligram of thyroxin was followed after an 

 interval of nine or ten days by a marked increase in activity. 

 One year later, injections of 0.25 mg. of thyroxin every 

 second day were again followed in three days by a pronounced 

 increase in neuro-muscular activity. Another cretin sheep of 

 about the same age as the first and thyroidectomized at the 

 same time received daily injections of one fourth milligram of 

 thyroxin during a period of prostration four and one-half months 

 after the extirpation of the thyroid. In this case the rise in the 

 activity curve occurred three days following the first injection. 

 One year later, thyroxin was again administered in doses of 

 0.25 milligrams every second clay and the sudden increase in 

 activity began after a latent period of six days. 



The other two cretin sheep (one of which had previously 

 thyroxin, the other having been fed thyroid extract) both gave 

 essentially the same reaction as the two preceding sheep to daily 

 injections of one-half milligram of thyroxin. The latent periods 

 were in one case, five days for the first series of injections and 

 four days for a similar series of thyroxin injections eleven 

 months later. In the other case, the interval between the be- 

 ginning of treatment and a marked increase in activity was 

 six days. 



One cretin sheep less active than the normal, showed no in- 

 crease in activity following the ingestion of one-half gram of 

 sodium iodide every second day for a period of sixty-three days. 

 In the ca-e of another thyroidectomized sheep which was fed 



