THE THYROTROPIC HORMONE 



(Herold, 1934; Scowen and Spence, 1936); however, this ap- 

 pears doubtful and was not confirmed by Rowlands and 

 Parkes (1936). Various investigators^" have experienced no 

 difficulty in confirming earlier experiments on the production 

 of thyrotropic antihormone; even with the best extracts 

 available, repeated injections soon appear to lose their 

 thyroid-stimulating properties, as is shown by the absence of 

 anatomical signs of thyroid stimulation and of physiological 

 changes, such as an increased basal metabolic rate due to the 

 increased liberation of thyroid hormone. The serum of blood 

 removed at this time prevents the thyrotropic action of an- 

 terior pituitary extract. Sometimes the antihormone effect 

 appears to be specific for the animal species furnishing the 

 pituitary tissue from which the extract was made (Eichbaum 

 and Kindermann, 1936; Gudet, 1937); in other experiments, 

 as in those of Thompson (1937), there seems to be no species 

 specificity, and the serum alone seems to cause atrophic 

 changes in the thyroid which resemble the condition follow- 

 ing hypophysectomy. An intermediate phenomenon was de- 

 scribed by Gudet, who concluded that species specificity is 

 present after a short course of injections but not after a long 

 course. A later report by Eichbaum and others (1937) sug- 

 gested that two types of antibody are formed — one character- 

 istic of the proteins of the species, the other characteristic of 

 thyrotropic hormone. 



Loeser (1936) has confirmed earlier experiments indicating 

 that hypophysectomy does not interfere with the formation 

 of thyrotropic antihormone. He continues to affirm (Eitel 

 and Loeser, 1935; and Loeser, 1936) that the presence of the 

 thyroid gland greatly facilitates the formation of antihor- 

 mone; but this is improbable and could not be confirmed 

 either by Gudet (1936) or by Chou (1937). 



Gkkels' experiments (1937) likewise indicate that tissues 



^° Extracts with thyrotropic effects were used in a number of the experiments 

 discussed in chap. iii. 



[ 193 ] 



