THE HORMONES IN HUMAN REPRODUCTION 



guinea pig, Hisaw and his young fellow students sought for 

 a hormone ("relaxin") in the corpus luteum. In the course of 

 this quest they obtained, and were the first to mention (1928), 

 although without exact definition, extracts having some of 

 the properties now known to be those of the corpus luteum 

 hormone. The matter of the supposed relaxative hormone, 

 incidentally, still remains a puzzle about which too little is 

 known to discuss it in this book. 



With one of these preparations Weichert (1928) was able 

 to duplicate Leo Loeb's experiment (described above) in a 

 castrated guinea pig; that is, the corpus luteum extract acted 

 upon the guinea pig's uterus so that in response to irritation 

 of its lining it produced masses of maternal cells as in preg- 

 nancy. This was confirmed by several of my students. Thus 

 the basic functions of the corpus luteum suspected by Ancel 

 and Bouin and by Loeb were confirmed by the use of extracts. 

 Fraenkel's findings were also soon repeated with the hormone, 

 for as soon as Willard Allen and I could prepare enough of 

 the extract, we were able (1930) to castrate female rabbits 

 at the eighteenth hour after mating and to carry the embryos, 

 by use of our extract, all the way to normal birth at the usual 

 term of pregnancy, in seven of our first fourteen attempts. 



It should be added that this is a tricky experiment about 

 which even yet we do not have full information. It seems to 

 require just the right amount of estrogen along with the pro- 

 gesterone. Perhaps we were lucky that our extract was just 

 sufficiently impure. At any rate it has turned out to be much 

 harder to accomplish the same result with chemically pure 

 progesterone. 



Although the experiments thus far cited were all done upon 

 the rabbit and guinea pig, there is no doubt that similar 

 effects are produced in other species, including the human. 

 In 1930 Hisaw and Fevold were able to produce progesta- 

 tional proliferation in the monkey, and the same result has 

 since been achieved many times in women by gynecologists 



( lU ) 



