384 



PHYSIOLOGY OF GONADS 



The anterior hypophysis may determine 

 indirectly the secretory activity of accessory 

 glands, and the amounts of fructose and 

 other chemical substances which accumlate 

 therein. Mann and Parsons (1950) showed 

 that hypophysectomy in the rabbit results 

 in a decline in the fructose content of semen, 

 and of the prostate gland and glandula ve- 

 sicularis. These changes were similar to those 

 induced by castration, and could be reversed 

 by treatment with androgens or with gonad- 

 otrophin. The deleterious effect of inanition, 

 or a deficiency of certain B vitamins, on 

 fructose formation in the accessory glands 

 is almost certainly related to a concomitant 

 depression of gonadotrophin secretion by the 

 anterior pituitary gland (Lutwak-Mann and 

 Mann, 1950 ) . In the bull (Davies, Mann and 

 Rowson, 1957j, underfeeding leads to a 

 greater depression of fructose levels in se- 

 men than of sperm formation. 



Analysis of fructose in excised ]irostate 

 gland or seminal vesicle has been used 

 widely as an indicator of androgenic activ- 

 ity. This procedure has yielded much infor- 

 mation concerning the relationship between 

 the time of onset of androgen secretion by 

 the testes and the initiation of spermato- 

 genesis. In the rabbit (Davies and Mann, 

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

 1948), bull (Mann, Davies and Humphrey, 

 1949), boar (Mann, 1954b), and guinea pig 

 (Ortiz, Price, Williams-Ashman and Banks, 

 1956) , fructose can be detected in the acces- 

 sory glands before spermatozoa are pro- 

 duced. The androgenic potency of exogenous 

 substances can be determined by application 

 of the fructose test to the accessory glands 

 of animals castrated before or after puberty. 

 The increase in fructose content of the co- 

 agulating gland of castrated rats in response 

 to testosterone is greater than the corres- 

 ponding change in organ weight (Mann and 

 Parsons, 1950) . The prostate gland and sem- 

 inal vesicle of the rat (Rudolph and Samuels, 

 1949; Rudolph and Starnes, 1955; Rauscher 

 and Schneider, 1954) and the seminal vesicle 

 of the guinea pig (Levey and Szego, 1955b; 

 Ortiz, Price, Williams-Ashman and Banks, 

 1956) behave in a similar fashion. This tech- 

 nique has provided evidence for the slight 

 androgenic activity of progesterone (Price, 

 Mann and Lutwak-Mann, 1955), and for 

 the antagonistic (Parsons, 1950) or syner- 



gistic (Gassner, Hill and Sulzberger, 1952) 

 influence of estrogens on the action of andro- 

 gens. 



Intact vascular and neural links are not 

 necessary for the male accessory glands to 

 accumulate fructose after androgenic stimu- 

 lation. Subcutaneous transplants of these 

 tissues into male rats will grow and produce 

 fructose. After castration, the fructose con- 

 tent falls and can be restored by testosterone 

 therapy (Mann, Lutwak-Mann and Price, 

 1948). Fructose secretion was also observed 

 in accessory tissues transplanted into female 

 hosts which had received androgens (Lut- 

 wak-Mann, Mann and Price, 1949), or were 

 injected with gonadotrophins. which prob- 

 ably stimulate the secretion of ovarian an- 

 drogens (Price, Mann and Lutwak-]Mann, 

 1955). 



The fructose in seminal i^lasma serves as 

 a source of energy for spermatozoa under 

 both anaerobic and aerobic conditions 

 (Mann, 1954a). 



Sorbitol. Sorbitol has been detected in the 

 seminal vesicles of the sheep ( Hers, 1957a, 

 b) and the coagulating gland of the rat 

 (Wolfson and Williams-Ashman, 1958), as 

 well as in the semen of many species ( King, 

 Isherwood and Mann, 1958; King and Alann, 

 1958, 1959). The sorbitol content of semen 

 tends to be high in those animals which ex- 

 hibit high levels of seminal fructose, al- 

 though it is also present in the semens of the 

 stallion and cock, which are virtually devoid 

 of fructose (Table 6.3). Sorbitol can be syn- 

 thesized in the accessory glands by the 

 action of either ketose reductase (Williams- 

 Ashman and Banks, 1954a; Williams-Ash- 

 man, Banks and Wolfson, 1957; Hers, 1956, 

 1957a) or aldose reductase (Hers, 1956, 

 1957a). Under anaerobic conditions, sper- 

 matozoa will not glycolyze sorbitol (unlike 

 fructose) to lactic acid, but will reduce both 

 fructose and glucose to sorbitol. In oxygen, 

 spermatozoa readily oxidize sorbitol (Mann 

 and White, 1956), and also form sorbitol 

 from glucose and fructose. The interconver- 

 sion of fructose and sorbitol by spermatozoa 

 is catalyzed by a DPN-specific ketose re- 

 (Uictas(> (sorbitol dehydrogenase) which is 

 similar to that of the accessory glands 

 (King and ^Nlann, 1959). Although the sper- 

 matozoa can affect the ratio of the levels of 

 soi'bitol and fi-uctose in seminal plasma, 



