THE PITUITARY BODY 



Wolfe (1931) investigated the potency of the pars glandularis 

 of the pig in causing ovulation in the rabbit. If the anterior 

 lobe was removed from pigs in pro-oestrus or just before the 

 first oestrus, the dose of fresh gland required to produce ovu- 

 lation was 1-2 mg. About 10 mg. was required if the pitui- 

 tary was removed during oestrus. The largest doses (about 40 

 mg.) of anterior pituitary required were from pigs in the 

 ovaries of which were found actively secreting corpora lutea. 

 The effects of gonadotropic hormones (from the pituitary of 

 the horse and the pig, and from the serum of pregnant mares) 

 on the ovary of the immature pig 1-112 days old were in- 

 vestigated by Casida (1935). Different effects (follicle 

 growth, hemorrhage into follicles, ovulation, and the forma- 

 tion of corpora lutea) were produced, but these depended 

 upon the preparation used, the manner of administration, 

 the age of the pig, the development of the ovaries, etc. The 

 extracts had little or no effect on the ovaries of pigs younger 

 than 5 weeks. In comparison with the effect on the ovary of 

 the immature rat, luteinization was less easily produced in 

 the ovary of the immature pig. 



The pars glandularis of the horse contains a higher concen- 

 tration of the gonadotropic hormone(s) than that of any 

 other large animal (Hellbaum, 1933; Hill, 1934). This ap- 

 pears to be true particularly of the castrated horse. In imma- 

 ture rats, unrefined extracts of the anterior lobe of the (cas- 

 trated) horse cause chiefly a follicle-growth, whereas those of 

 the sheep cause luteinization as well. The experiments of 

 Catchpole and Lyons (1934), who used material from preg- 

 nant mares, are referred to later. 



2. The mouse^ rat, and guinea pig. — The general effects of 

 implants of the anterior pituitary on the gonads of immature 

 mice and rats and of adult rats have already been described 

 in the introductory part of this chapter. In this section some 

 of the special effects of gonadotropic extracts will be con- 

 sidered. 



[130] 



