GONADS AND THE PITUITARY BODY 



smaller than those of pregnancy (Zondek and Aschheim, 

 1928). 5*^ Teel (1926) injected a crude extract of the anterior 

 lobe of the ox into rats from the day of impregnation until 

 delivery. He concluded that this treatment, which may cause 

 the excessive formation of lutein tissue in adult females, re- 

 sulted in a prolonged gestation period (25-29 days instead of 

 23) probably because implantation was delayed. Further- 

 more, the fetuses were usually still-born; if they were re- 

 moved at about the time of normal term, they could be 

 nursed by the mothers. Similar but less pronounced effects 

 were observed by Sontag and Munson (1934), who used a 

 more refined extract of the anterior pituitary of the ox. The 

 new-born fetuses from the injected mothers were heavier than 

 the fetuses of normal mothers (14 per cent in Teel's series, 

 and 7 per cent in the series of Sontag and Munson); in both 

 sets of experiments the gestation period was prolonged. 



Different results were obtained by Engle and Mermod 

 (1928), who administered homoplastic or heteroplastic pitui- 

 tary implants (mouse, rat, rabbit) to pregnant mice and rats. 

 This treatment, in the first part of pregnancy, either pre- 

 vented implantation or caused the resorption of the fetuses. 

 In the middle third of pregnancy either abortion or fetal re- 

 sorption followed the administration of implants; a similar 

 effect was much less frequently observed in the last third of 

 pregnancy, at the end of which normal litters were usually 

 born. The authors were inclined to attribute the effects to the 

 increased liberation of follicular hormone resulting from fol- 

 licular stimulation." 



According to Kelly (1933), the fluid which can be expressed 

 from the anterior lobe, if administered to pregnant guinea 

 pigs, does not prevent implantation but does cause abortion 

 (twenty-seventh to fifty-second day of pregnancy). He made 



5^ Also see Siegmund (1929). 



5' The injection of oestrin into pregnant rats either prevents implantation, or, 

 if given later, terminates the pregnancy (see D'Amour and Gustavson, 1934). 



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