THE HORMONES IN HUMAN REPRODUCTION 



had achieved the total synthesis of an estrogenic hormone,^ 

 building it up in the laboratory from simple materials. These 

 examples of chemical magic made a fitting climax to years of 

 brilliant work on estrogenic hormones by the chemists of many 

 nations. 



A substance as complicated as this affords many oppor- 

 tunities for slight modifications by rearrangement, addition, 

 or subtraction of the constituent atoms. It is not surprising, 

 therefore, that a whole series of estrogenic hormones has 

 been found, each differing slightly from estrone in chemical 

 structure and in potency or even in details of physiological 

 action. These have been obtained from the urine of other 

 species (as for example equilenin from the mare), from male 

 urine and from the human placenta. 



It is a curious fact that Allen and Doisy's originally dis- 

 covered hormone of the swine ovary, being immensely difficult 

 to purify because of all the fats, oils and proteins of the tis- 

 sues that come out in the extract with the hormone, was not 

 actually identified for a long time. Finally MacCorquodale, 

 Thayer and Doisy in 1935 extracted two tons of ovaries and 

 obtained as the chief active substance a few milligrams of a 

 compound differing from estrone only in having an OH group 

 at position 17 instead of the doubly-bonded oxygen. This is 

 estradiol. It is probably the form which is actually made in 

 the ovary. 



It has been found that esters of these hormones, i.e. com- 

 binations of estrogens with organic acids, are more slowly 

 eliminated from the body than the estrogens themselves and 

 therefore give longer and more intense effects. The propionic 

 and benzoic esters have been widely used in the treatment of 

 human patients. 



Chemists are always interested to know just what part or 

 feature of such a molecule is responsible for its effects. They 



2 Actually not estrone, but equilenin, referred to in the following 

 paragraph. 



{ 88 } 



