4o6 SECTIONAL TRANSACTIONS— B. 



steric configuration. One of the possible two steric configurations is in 

 each case more active physiologically and the physiological diflference 

 between compounds possessing these two configurations is greatest in the 

 case of compounds differing in the 5 -position, whereas position 17 has less 

 influence and position 3 the least influence. With reference to position 5, 

 that configuration is favoured physiologically which consists in a trans 

 configuration of the rings A and B. The corresponding cis isomers are 

 physiologically quite inactive. On carbon atom 17 the trans position of 

 the hydroxyl with respect to the neighbouring methyl group leads to 

 increased activity compared with the corresponding cis compounds, and on 

 carbon atom 3 the isomers showing cis configuration of the hydroxyl with 

 respect to the hydrogen in 5 are physiologically more active. 



3'-^ "" 



s 



The introduction of a double bond in position 5 leads only to a slight 

 alteration in physiological activity. Moreover the double bond does not 

 appear to be intimately concerned with testosterone-like activity when 

 compared with the corresponding saturated derivatives. Of importance, 

 however, is the presence of a keto group in position 3 which, in respect to 

 the action on the seminal vesicles and prostate, is greatly superior to the 

 corresponding hydroxyl derivative. A reversed relationship appears to 

 exist for carbon atom 17 where a hydroxy group is found to be more active 

 than a keto group. 



An increased activity of testosterone when it is injected in oil solution 

 can be obtained by esterification, especially the propionate shows remarkably 

 enhanced activity. 



It is established that a whole series of androstane derivatives show a 

 weak cestrogenic activity. ' It is not possible to define the details of the 

 chemical structure characteristic for this activity in such an exact way as 

 it is possible to determine the structural details associated with andro- 

 genic activity. It seems, however, that the presence of a double bond in 

 position 5 is of essential importance for the cestrogenic activity of androgens. 

 For progesterone-like activity in androstane derivatives the double bond 

 also appears to be necessary. 



Dr. A. S. Parkes. — Multiple biological activities of hormones and allied 

 substances (10.40). 



The gonadal hormones and allied substances fall into three classes : the 

 oestrone group, the progesterone group, and the androsterone-testosterone 

 group. The substances of the first group, of which the better known are 

 cestrone, oestradiol and oestriol, have primarily the power to evoke in the 

 female reproductive tract the changes characteristic of the time of ovulation. 

 In the male, these substances have an effect on the accessory reproductive 

 organs, causing metaplasia of the epithelium or hypertrophy of the fibrous 

 tissue, or both, according to the species of animal and the duration of 

 treatment. No activity which can be called specifically androgenic is 

 shown by these compounds. In both sexes the cestrogens depress pituitary 

 activity, as may be seen by the effects on growth and on the gonads. 



Progesterone has primarily the power to cause progestational changes in 

 the female reproductive tract. It has little direct effect on the reproductive 



