THE HORMONES IN HUMAN REPRODUCTION 



blocked, so that these females ovulated but did not become 

 pregnant. The corpora lutea, which under these circumstances 

 would normally degenerate after about 14 days, were made to 

 persist by the pituitary hormones. The expectations of the 

 experimenter were brilliantly fulfilled by the occurrence of 

 mammary growth and lactation. When the report of these 

 experiments reached the United States, we had in our Uni- 

 versity of Rochester laboratory a fair amount of the then 

 new corpus luteum hormone in crude form (progestin) and 

 took the obvious step of trying to produce mammary growth 

 and lactation with the progestin alone. To my surprise we got 

 no lactation and no marked growth of the mammary gland. 

 From this failure, however, an important deduction could be 

 made. Parkes had subjected his rabbits to the action of two 

 hormones (pituitary and corpus luteum) ; I had given only 

 the latter. He obtained lactation, I did not. Subtracting my 

 procedure from his, it looked as if the anterior pituitary hor- 

 mone was the only necessary factor. We made up a flask of 

 pituitary extract from sheep and injected it into six adult 

 castrated virgin female rabbits. In 3 days milk began to drip 

 from their nipples ; in 10 days the mammary glands had thick- 

 ened and spread all over the chest and belly as in advanced 

 pregnancy and when we milked them the milk spurted across 

 the room. 



I thought at first that this discovery of the lactogenic 

 potency of the anterior lobe of the pituitary was completely 

 new, but study of the scientific journals revealed that a few 

 months previously two Alsatians, Strieker and Grueter, 

 working in Strasbourg in the laboratory of Paul Bouin, had 

 done exactly the same experiment with the same result. By 

 what process of logic they were led to try it was not narrated 

 in their report. 



The extracts were very crude and we set out to purify 

 them. One of the large drug houses provided more extract by 

 the quart and one of their research staff started to work out 



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