THE PITUITARY BODY 



secreted in response to the injection of thyrotropic hormone. 

 After the injection of the latter, the heart rate begins to rise 

 within an hour and is 30-50 per cent more rapid after 7-9 

 hours. On the other hand, even after 4 mg. of thyroxine the 

 heart rate is not significantly changed within a day. The 

 authors' other comparisons of the effects of repeated doses 

 appear to be less significant. Page and Sweet (1937) pro- 

 duced hypertension in dogs by means of Goldblatt's clamp. 

 After hypophysectomy the blood pressure fell but could be 

 raised moderately by the daily administration of 0.8 gm. of 

 desiccated thyroid. The authors suggest that the lack of 

 thyrotropic hormone following the removal of the hypophy- 

 sis may account partly for the fall in blood pressure in dogs 

 with experimental hypertension. 



Anderson and Alt (1937) found that the addition of thyro- 

 tropic hormone to slices of isolated canine thyroid increased 

 the oxygen-consumption of the tissue 17-120 per cent per 

 hour during the first 3 hours; a similar change could not be 

 produced if isolated slices of liver or kidney were used. These 

 observations confirm the earlier report of Eitel, Krebs, and 

 Loeser. 



Either thyrotropic hormone or thyroid extract brings about 

 a reduction in the concentration of hepatic glycogen. This 

 effect appears not to be modified by the administration of KI 

 (Holden and Thurston, 1935). Another action on carbo- 

 hydrate metabolism attributed to the thyrotropic hormone is 

 an increased rate of liberation of insulin in dogs, whether or 

 not the vagi have been cut (Zunz and La Barre, 1935). Con- 

 firmatory experiments were performed in non-anesthetized 

 dogs by Kotchneff and London (1937), who concluded that 

 the concentration of insulin in the blood may be quadrupled 

 30 minutes after the injection of extract containing 20-60 

 units of thyrotropic hormone. There appeared to be no effect 

 on the rate of liberation of epinephrine. After the repeated 

 injection of thyrotropic hormone into guinea pigs, the heart 

 undergoes considerable hypertrophy (about 60 per cent in 



[ 188I 



