THE HORMONES IN HUMAN REPRODUCTION 



droxyl group at carbon 3, and an atom of oxygen at carbon 

 17; in other words it is 3-hjdroxy, 17-keto estratriene (for 

 clearness, the formula is written in full as well as in the usual 

 simplified form) : 



HO-C^^/C^^^CH^ 



ESTRONE 



ESTRONE 



As explained in Chapter IV, a large series of naturally 

 occurring estrogens is known. All these are closely related to 

 estrone. Among the representative estrogens are the follow- 

 ing: 



Estradiol, the hormone which probably exists in the great- 

 est amount in the body, has a hydroxyl group at position 17 

 instead of the doubly-linked (ketonic) oxygen: 



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