396 



PHYSIOLOGY OF GONADS 



Kaplan and Ciotti, 1959; c/. Talalay, Hur- 

 lock and Williams-Ashman, 1958). These 

 mitochondrial transhydrogenases do not re- 

 quire steroid hormones as cof actors. Accord- 

 ing to Hmiiphrey (1957), the large cyto- 

 plasmic particles of rat prostate gland and 

 seminal vesicle are devoid of transhydro- 

 genase activity. Slices of human prostate 

 gland convert testosterone to androst-4- 

 ene-3,17-dione (and other metabolites) 

 (Wotiz and Lemon, 1954; Wotiz, Lemon 

 and Voulgaropoulos, 1954). This suggests 

 that the human prostate contains a 17/3- 

 hydroxysteroid dehydrogenase which could 

 conceivably function as a transhydrogenase 

 in the presence of low levels of testosterone. 

 Baron, Gore and Williams (1960) reported 

 the presence of androsterone-stimulated 

 transhydrogenase reactions in the prostate 

 gland of rodents and man. On the contrary, 

 Williams-Ashman, Liao and Gotterer 

 (1958), and Samuels, Harding and Mann 

 (1960) were unable to demonstrate any ac- 

 tivation by testosterone of hydrogen trans- 

 fer between TPNH and DPN in rat pro- 

 static tissue. DPNH and TPNH serve 

 rather different metabolic functions (c/. 

 Talalay and Williams-Ashman, 1958), and 

 it is possible that steroid-mediated trans- 

 hydrogenations might exert a controlling 

 influence over the balance between the oxi- 

 dized and reduced forms of pyridine nucleo- 

 tides in the extramitochondrial regions of 

 certain cells. However, at present there is no 

 direct evidence in support of this hypothesis 

 (cf. Talalay and Williams-Ashman, 1960). 



E. COAGULATION OF SEMEN 



Mammalian semen is emitted from the 

 urethra as a liquid. In some species, e.g., 

 the bull and the dog, the semen remains 

 permanently in the liquid state. But the 

 seminal fluid of many other mammals may 

 undergo remarkable changes in its physical 

 IM^operties on standing. Rodent semen clots 

 rapidly and, if ejaculated into the vagina, 

 forms a solid vaginal plug. This structure 

 assists fertilization by preventing an out- 

 flow of semen from the vagina after copu- 

 lation (Blandau, 1945). The subsequent 

 dissolution of the vaginal plug, probably 

 as the result of the action of leukocytic en- 

 zymes, was studied by Stockard and Pajia- 

 nicolaou (1919). A copulatory plug lias 



also been described in certain Insectivora, 

 Chiroptera, and Marsupiala (Camus and 

 Gley, 1899; Engle, 1926a; Courrier, 1925; 

 Eaclie, 1948a, bj. 



It has been stated that in the opposum 

 (Hartman, 1924) and in the bat (Courrier, 

 1925), the vaginal plug results from the 

 coagulation of the female secretions by 

 seminal plasma. However, the semen of 

 many other species clots on its own accord. 

 Camus and Gley (1896, 1899) were the 

 first to recognize that in the rat and guinea 

 pig, the clotting process involves the solidi- 

 fication of the vesicular secretion by an 

 enzyme of prostatic origin, which they 

 termed vesiculase. The classical experi- 

 ments of Walker (1910a, b) showed that 

 this enzyme is secreted solely by the an- 

 terior prostate or "coagulating" gland. In 

 the rhesus monkey, the secretion of the 

 cranial lobe (but not of the caudal lobe) of 

 the prostate gland coagulates the vesicular 

 secretion (van Wagenen, 1936) . The "soft 

 calculus" frequently present in the urinary 

 bladder of male but not female rats is 

 l^robably formed by clotting of the seminal 

 vesicle secretion by the action of enzymes 

 from the coagulating gland (Vulpe, Usher 

 and Leblond, 1956) . 



More recently, the mechanism of action 

 of vesiculase has been studied in consider- 

 able detail. A crude preparation of the pro- 

 teins of the vesicular secretion that are 

 clotted by this enzyme can be obtained in 

 a stable form, and the clotting process may 

 l)e measured quantitatively by simple spec- 

 trophotometric procedures (Gotterer, Gins- 

 burg, Schulman, Banks and Williams-Ash- 

 man, 1955; Gotterer and Williams-Ashman, 

 1957; Zorgniotti and Brendler, 1958). The 

 over-all coagulation process is extremely 

 sensitive to the ionic strength of the solu- 

 tion in which it takes place, and is abolished 

 by the addition of metal chelating agents 

 such as Versene (ethylcnediaminetetra- 

 acetic acid), o-i)henanthroline, and a,a- 

 dipyridyl, and also by heavy metals such 

 as mercuric ions. The inhibitory action of 

 Versene can be overcome by manganous 

 ions, or by somewhat higher concentrations 

 of calcium ions. Experiments involving the 

 delayed addition of either heavy metal ions 

 or of metal chelating agents established that 

 till' coagulation process can be separated 



