THE PITUITARY BODY 



produce ovulation by injecting salts of pilocarpine or physo- 

 stigmine intravenously. However, the injection of atropine 

 sulphate, if given at an appropriate time, seemed to prevent 

 ovulation or pregnancy (if ovulation had already occurred). 



A number of authors have confirmed Bellerby's observa- 

 tion (1929, 1934) that the intravenous injection of an extract 

 of the pars glandularis (in this case, of the ox) is followed in 

 about 1 1 hours by ovulation whether or not the hypophysis 

 has been removed previously.'^ Most of the authors used ex- 

 tracts of the anterior pituitary of the ox or the sheep. How- 

 ever, it appears that the pars glandularis of all mammals is 

 capable of causing ovulation in the rabbit provided that a 

 suspension or extract of the gland is given intravenously. 

 Subcutaneous or intraperitoneal injections usually cause fol- 

 licular growth and — if the dose is large — atretic corpora lutea 

 which may be hemorrhagic.'^ Hemorrhages are also frequent- 

 ly observed in large or growing follicles. Similar ovarian 

 changes may follow the intravenous injection of anterior-lobe 

 extracts. Once ovulation has been produced, either by the 

 secretion of the rabbit's own pituitary or by the injection of 

 an anterior-lobe extract, the growth and maintenance of the 

 corpora lutea do not require the secretion of the animal's own 

 pituitary until about 2 days later. By means of suitable doses 

 of extract, ovulation can be produced in immature, pseudo- 

 pregnant, or pregnant rabbits. 



The dose of an anterior-lobe extract which will produce 

 ovulation in an adult rabbit in oestrus may be less than one- 

 fifth of the dose of the same extract required to cause an 

 ovarian hypertrophy in the immature rat (Leonard, 1932). 

 Hill (1934) has investigated the concentration of the ovula- 

 tion-producing hormone in the pituitary of a number of 

 mammals. 



'* Friedman (1930); Strieker and Grueter (1930); Hill and Parkes (1931); 

 Kunischige (1931); Leonard (1931); Jares (1932); and others. 

 '' But see Strieker and Grueter (1929). 



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