THE PITUITARY BODY 



Another metabolic effect of thyrotropic hormone/^ which 

 also is indirect and is the result of an increased liberation of 

 thyroid hormone, is the reduction of the concentration of 

 hepatic glycogen following adequate treatment. In the 

 guinea pig the maximum effect was not seen until after about 

 I week's treatment, but the effect might disappear a few 

 days later despite the continuation of treatment (Eitel and 

 Loeser, 1932; Holden, 1934). To produce a similar fall in the 

 concentration of hepatic glycogen in the rat, Eitel, Lohr, and 

 Loeser (1933) had to administer enormous doses of thyro- 

 tropic hormone (400 guinea pig-units daily) and yet they pro- 

 duced no significant histologic changes in the rat thyroid. 

 Thyroidectomy, however, prevented the effect of the extract 

 on the hepatic glycogen. According to Jonas (1934) the 

 glucose-tolerance is reduced in man (normal or with Graves's 

 disease) after the injection of an extract with thyrotropic 

 effects. This change is not related to the alteration in basal 

 metaboHc rate. The blood sugar remains unaltered unless the 

 liver has been damaged, when there may occur a hypo- 

 glycemia (Lucke, Heydemann, and Duensing, 1933; and 

 Horsters, 1933). However, in the dog under chloralose 

 anesthesia, the intravenous injection of a large dose of thy- 

 rotropic hormone causes a reduction in the concentration of 

 blood-glucose amounting to 11-18 mg. per cent (Zunz and 

 La Barre, 1934-35). This change is not observed in thy- 

 roidectomized dogs and apparently is due to an increased 

 liberation or secretion of insulin. The thyrotropic hormone is 

 said not to cause a loss of the hepatic glycogen of animals re- 

 ceiving levulose and insulin (Loeser, 1934). 



Some elevation of the concentration of ketone-bodies in the 

 blood was produced by the administration of large doses of a 

 purified thyrotropic hormone to normal but not thyroidec- 

 tomized rats (Eitel, Lohr, and Loeser, 1933). Feuling (1933) 



'7 Also see the hypothesis of Barnes (1934). 

 [270I 



