Fructose and Fructolysis 145 



doses of progesterone injected into castrated male rats have a 

 definite androgenic effect; it was calculated that the androgenic 

 value of 25 mg. pure progesterone is slightly more than that of 

 0005 mg. testosterone propionate (Price, Mann and Lutwak-Mann, 

 1949, 1954). 



Whereas progesterone exhibits some androgenic activity, stil- 

 boestrol is endowed with the properties of an androgen-antagonist. 

 The testosterone-catalysed secretion of fructose in the male accessory 

 gland secretions of a rabbit can be suppressed very effectively by the 

 subcutaneous implantation of 25 mg. stilboestrol (Parsons, 1950). 

 In experiments in which a castrated rabbit received simultaneously 

 implants of testosterone and stilboestrol, the latter prevented com- 

 pletely the production of fructose by the accessory organs. 



It appears that in castrated bulls, small amounts of oestradiol 

 dipropionate used together with testosterone, have a small but 

 definite synergistic effect on the seminal vesicles and lead to a higher 

 output of fructose in semen (Gassner, Hill and Sulzberger, 1952). 



Role of hypophysis 



The endocrine influence of the testes on the formation of fructose 

 in accessory organs is integrated closely with the functioning of the 

 anterior pituitary gland. Hypophysectomy, like gonadectomy, invari- 

 ably results in a rapid decline in the level of fructose in the seminal 

 plasma (Mann and Parsons, 1950). In the rabbit, for instance, a 

 three to four weeks' period after castration or hypophysectomy alike, 

 usually leads to complete disappearance of fructose so that an 

 ejaculate collected by means of an artificial vagina three weeks 



Table 21. Ejfect of testosterone and pregnant mare serum 

 gonadotrophin on the formation of fructose in rabbit prostate 



Weight of Fructose 



prostate content 



Rabbit (mg.) (//g. /organ) 



1. Normal 770 935 



2. 3 weeks after castration 280 20 



3. 6 weeks after castration and simultaneous 



implantation of testosterone (100 mg.) 1000 1220 



4. 4 weeks after hypophysectomy 149 10 



5. 6 weeks after hypophysectomy; for the last 



4 weeks injected 200 I.U. PMS-gonado- 



trophin 210 395 



