THE PITUITARY BODY 



The authors concluded that it antagonizes the action of folli- 

 cle-stimulating hormone but not luteinizing hormone and 

 that it acts independently of the pituitary, thyroid, or adre- 

 nals. Some of its described effects suggest that it is luteinizing 

 hormone: it has no action on the ovaries of normal immature 

 rats, but it causes or permits extensive luteinization of the 

 ovaries of adult rats and prolongs pregnancy, if injected in 

 the last half of pregnancy. Evans and his colleagues suggest 

 that such a substance may be important physiologically. It 

 is obvious that its presence in extracts may complicate all 

 studies of the effects of gonadotropic extracts, including in- 

 vestigations of antihormones (see the following section)." 

 Leonard, Hisaw, and Fevold (1935) concluded that the in- 

 hibitory substance is associated with luteinizing hormone, 

 although follicle-stimulating hormone, also injected intra- 

 peritoneally, might produce some inhibition. It is the belief 

 of Jensen (personal communication) that luteinizing hor- 

 mone, "pituitary antagonist," and "interstitial cell stimulat- 

 ing hormone" are one and the same principle. 



Freud (1937) believed that he had detected an "antiluteo- 

 genic factor" in extract of the pars glandularis of the ox. He 

 suggested that the absence of this substance accounts for the 

 persistence of corpora lutea in hypophysectomized rats. 

 (Bunde and Greep [1936] considered this to be owing to a lack 

 of luteinizing hormone or some substance associated with it.) 

 Two early pregnancies in rats were interrupted by intraperi- 

 toneal injections of the extract — a fact which the author in- 

 terprets as supporting his view that the injected substance 

 antagonized the luteinizing hormone. 



3. The augmentation of the ef^ects of gonadotropic extract. — 

 A variety of substances may potentiate or augment the ac- 

 tion of a gonadotropic extract. For example, the hypertrophy 



"s Evans concluded that the immature pigeon's testis is very sensitive toward 

 gonadotropic extract, because it is unaffected by "pituitary antagonist" (see also 

 Bates, Riddle, and Lahr, 1935). 



[116I 



