392 



PHYSIOLOGY OF GONADS 



nal plasma by Lundquist and Seedorf 

 (1952). Three other proteolytic enzymes 

 were partially purified from human semen 

 by Lundquist, Thorsteinsson and Buus 

 (1955). The first enzyme resembled chymo- 

 trypsin, and the second was an aminopepti- 

 dase. The third enzyme hydrolyzed benzo- 

 ylarginine ethyl ester, and seems to be 

 identical with the arginine ester hydrolyz- 

 ing enzyme described in male accessory re- 

 productive glands by Gotterer, Banks and 

 Williams-Ashman (1956). The relationship 

 of these enzymes to the hydrolysis of fibrin 

 or fibrinogen by prostatic secretion is dis- 

 cussed below with reference to the coagula- 

 tion and liquefaction of semen. 



(7) Glycosidases. Using phenolphthalein 

 glucuronide as a substrate, Talalay, Fish- 

 man and Huggins (1946) determined the 

 /?-glucuronidase activity of the male ac- 

 cessory glands of the rat. The levels of this 

 enzyme in the epididymis fall about 50 per 

 cent after castration, and can be restored 

 to normal levels by the administration of 

 testosterone (Conchie and Findlay, 1959). 

 When the corresponding phenol- or p-nitro- 

 phenol-glycosides were employed as sub- 

 strates, Conchie, Findlay and Levvy (1956) 

 showed that the epididymis of the rat is 

 particularly rich in y3-iV-acetylglucosamini- 

 dase. The levels of this enzyme were found 

 by Conchie and Mann (1957) to be very 

 much greater than those of seven other 

 glycosidases in male accessory secretions. 

 The levels of various glycosidases in the 

 epididymis of rodents increases enormously 

 at puberty. In adult animals the activity 

 of some of these enzymes {e.g., a-manno- 

 sidase and /?-iV-acetylglucosaminidase) fell 

 to negligible values after castration, and 

 were restored only partially by treatment 

 with testosterone. 



(8) Miscellaneous enzipnes. The kneels of 

 a number of oxidizing enzymes in human 

 seminal plasma were studied by Rhodes and 

 Williams-Asluiuiii (1960», who noted the 

 presence of a x'cry active TPN-linked iso- 

 citric dehydrogenase. The ability of luiinan 

 semen to hydrolyze acetylclioline is rather 

 fe(>!)le, and the bulk of the activity resides 

 in the seminal plasma (Zeller and Joel, 

 1941). According to Sekine (1951), boar 

 semen exhibits powerful choline esterase 

 activity, wliicli is confined mainly to the 



s])ermatozoa. The activity of phosphohexo- 

 isomerase (Wiist, 1957) and lactic dehy- 

 drogenase (MacLeod and Wroblewski, 

 1958) in human seminal plasma has been 

 documented. 



The levels of the following soluble en- 

 zymes have been determined in the acces- 

 sory glands of male rodents: phenol sulfat- 

 ase (Huggins and Smith, 1947). nonsi)ecific 

 esterase (Huggins and ]\Ioulton, 1948), 

 enolase, and dehydrogenases for lactate, 

 malate, glucose 6-phosphate, 6-phosphoglu- 

 conate and isocitrate (Williams- Ashman, 

 1954; Rudolph, 1956), aldolase and a-glyc- 

 ero])hosphate dehydrogenase (Butler and 

 Schade, 1958). The nucleoside phosphoryl- 

 ase and adenosine deaminase activities of 

 bull seminal vesicle were measured by 

 Leone and Santoianni (1957). The vesicu- 

 lar secretion of the bull is rich in flavins, 

 and exhibits strong xanthine oxidase ac- 

 tivity (Leone, 1953). Leone and Bonaduce 

 (1959) described a very active diphospho- 

 ]5yridine nucleotidase in the vesicular secre- 

 tion of the bull. 



Conclusions. The foregoing survey indi- 

 cates that, just as the size and morphology 

 of the accessory glands differ profoundly, 

 so there are wide species variations in the 

 chemistry of their secretions, which com- 

 prise the seminal plasma. Some seminal 

 constituents {e.g., fructose) are found in 

 many mammals. Other substances, such as 

 ergothioneine, are present in appreciable 

 amounts in the seminal plasma of only a 

 few species. The biochemistry of the acces- 

 sory glands is still in its infancy, and it 

 may be expected that future research will 

 disclose other species-restricted comjionents 

 of seminal plasma. Mann (1954a, 1956) 

 I'ightly emphasizes that the finding of sub- 

 stantial concentrations of certain sub- 

 stances in the semen of only relatively few 

 species does not necessarily detract from 

 their physiologic value. The high levels of 

 ci-gotliioneine in the seminal plasma of the 

 boar and stallion is a case in point. The 

 cjacuhitcs of these species have peculiarities 

 which may render their spermatozoa par- 

 ticularly susceptible to the immobilizing 

 action of oxidizing agents, and the sugges- 

 tion (Mann and Leone, 1953; IMann, Leone 

 and Polge, 1956) that ergothioneine, in vir- 

 tue of its reducing properties, serves a pro- 



