144 The Biochemistry of Semen 



preservation of intact vascular and neural links. Insight into this 

 matter was gained by the technique of subcutaneous transplantation, 

 when it was demonstrated that small fragments of rat coagulating 

 gland, about 1 mg. in weight, transplanted subcutaneously into 

 normal adult male hosts, grew well and showed after some weeks 

 of subcutaneous development a high content of fructose. Follow- 

 ing castration of the hosts, the transplants lost their ability to 

 form fructose but this was promptly restored by treatment with 

 testosterone propionate. Perhaps the most remarkable fact in these 

 experiments was that the growth of the grafts and their chemical 

 secretory function occurred not only in male, but also in female 

 hosts provided that the latter were treated with testosterone 

 (Lutwak-Mann, Mann and Price, 1949). 



Thus, for the first time the effect of the male sex hormone on 

 fructose secretion was demonstrated in tissue fragments dissected 

 from the male accessory organs and developing in complete isola- 

 tion from the rest of the male generative system. Actually, the trans- 

 plants had an even higher fructose content than the corresponding 

 intact glands of the graft-bearing hosts, because unlike intact glands, 

 the grafts lack a secretory outlet. 



In another study, Price, Mann and Lutwak-Mann (1949, 1954) 

 applied the transplantation technique, coupled with the chemical 

 methods, to the problem of the androgenic activity of ovarian 

 hormones in the female rat. Subcutaneous transplants of rat coagu- 

 lating gland in female hosts were shown to secrete large quantities 

 of fructose in response to injections of pregnant mare serum gona- 

 dotrophin. A series of thirty injections of twenty international units 

 of equine gonadotrophin was given daily; at autopsy the ovaries of 

 the female hosts were enlarged at least tenfold and covered with 

 numerous follicles and corpora lutea. In these rats, gonadotrophin, 

 through a stimulating action on the ovaries, raised the output of 

 ovarian androgens to an extent which induced the secretion of fruc- 

 tose in transplants from the coagulating gland. 



{d) Effects of progesterone, stilboestrol and oestradiol. The nature 

 of the ovarian androgen responsible for the formation of fructose 

 is unknown, but there are indications that it may be related to 

 progesterone or to a product of progesterone metabolism. An 

 inquiry into the androgenic value of progesterone showed that large 



