44 



The Biochemistry of Semen 



(1948c) found 155 mg. K/lOO ml. seminal plasma. In the higher 

 mammals, the content of potassium in semen may reach 400 mg./ 

 100 ml. (Table 4); it is derived mainly from the seminal plasma where 

 it is found at least partly, in association with citric acid (see p. 188). 



Hydrogen ion concentration and buffering capacity 



The reaction of freshly ejaculated semen is not far from neutral 

 (Table 8). On standing, the semen may become alkaline at first, 

 unless precautions are taken to prevent the loss of carbon dioxide, 



Table 8. Hydrogen ion concentration in semen 



References 



McKenzie, Miller and Bauguess (1938) 



Anderson (1942); Hatziolos (1937) 



Laing (1945) 



Zagami (1939) 



Lambert and McKenzie (1940) 



Zagami (1939) 



Starkov (1934) 



Zagami (1939) 



Huggins, Scott and Heinen (1942) 



Zagami (1939) 



Lambert and McKenzie (1940) 



McKenzie and Berliner (1937) 



Nishikawa and Waide (1951) 



Hayashi (1945) 



Rothschild (1948c) 



but later this change is followed, at least in those specimens which 

 contain fructose and a high concentration of spermatozoa, by a 

 rapid decrease of pH, owing to fructolysis and accumulation of 

 lactic acid. Excessive initial alkalinity of semen in some species, 

 notably in bulls and rams, often accompanies low fertility, the 

 alkaline reaction being associated with absence or low concen- 

 tration of sperm and with a correspondingly higher proportion of 

 seminal plasma. A significant negative correlation between the pH 

 value and sperm density and motility has been noted frequently 

 in bulls and rams (cf. Anderson, 1945); in the latter, according to 

 McKenzie and Berliner (1937), normal semen is slightly acid or at 



