ACCESSORY MAMMALIAN REPRODUCTIVE GLANDS 



391 



1940). High levels of acid })hosphatase are 

 also present in osteoplastic metastases of 

 prostatic carcinoma (Gutman, Sproul and 

 Gutman, 1936). Acid phosphatase does not 

 seem to enter the circulation from the pros- 

 tate gland in healthy individuals unless 

 they are subject to prostatic massage. But 

 in about 65 per cent of men with metastatic 

 carcinoma of the prostate, the serum levels 

 of this enzyme are abnormally high (Gut- 

 man and Gutman, 19381); Robinson, Gut- 

 man and Gutman, 1939; Huggins and 

 Hodges, 1941). The diagnosis and prognos- 

 tic evaluation of carcinoma of the prostate 

 in men has been aided greatly by measure- 

 ments of the acid phosphatase levels of 

 serum. Inhibition of the acid phosphatase 

 activity of blood serum by L-tartrate has 

 been used as an index for the outflow of 

 prostatic acid phosphatase into the serum 

 in neoplastic diseases of the prostate gland 

 (Abul-Fadl and King, 1948; Fishman and 

 Lerner, 1953). 



The prostate gland of the monkey (Gut- 

 man and Gutman, 1938a) and dog (Hug- 

 gins and Russell, 1946), and the seminal 

 vesicle of the guinea i)ig (Bern and Le\y, 

 1952) exhibit powerful acid phosphatase 

 activity, whereas the levels of this enzyme 

 in the prostate of the rabbit (Bern and 

 Levy, 1952) and rat (Huggins and Web- 

 ster, 1948) are relatively low. The proper- 

 ties of these enzymes from different species 

 are strikingly similar (Novales and Bern, 

 1953) . In the monkey and dog, the prostatic 

 acid jihosphatase activities are controlled 

 by androgenic hormones. This is also true 

 in the rat (Stafford, Rubinstein and Meyer, 

 1949), and guinea pig (Ortiz, Brown and 

 Wiley, 1957). 



{2} Alkaline phosphatase. An enzyme, 

 activated by magnesium ions, which hydro- 

 lyzes a variety of phosphate monoesters at 

 pH 9, is present in the seminal fluid and 

 accessory glands. In some species, e.g., the 

 l)ull (Reid, Ward and Salisbury, 1948 ) , the 

 levels of seminal alkaline phosphatase are 

 much greater than those of the acid phos- 

 phatase. In the rat, alkaline phosphatase 

 activity in the prostate and seminal vesicles 

 decreases markedly after castration (Staf- 

 ford, Rubinstein and Meyer, 1949). 



(3) 5'-Nucleotidase. Reis (1937, 1938) 

 noticed that human seminal plasma dcphos- 



phorylated adenosine 5'-phosphate and ino- 

 sine 5'-phosphate very rapidly. He proposed 

 the term ''5'-nucleotidase" for enzymes 

 which specifically hydrolyze the 5'-mono- 

 phosphates of ribose and its nucleosides. 

 Mann (1945) reported that bull seminal 

 plasma is exceedingly rich in 5'-nucleo- 

 tidase. The enzyme was purified from this 

 source by Heppel and Hilmoe (1951a). It 

 was inactive towards adenosine 2'- and 3'- 

 phosphates, but catalyzed the hydrolysis 

 of the 5'-monophosphate esters of adeno- 

 sine, inosine, cytidine, uridine, and ribosyl 

 nicotinamide. The 5'-nucleotidase of bull 

 semen is optimally active at pH 8.5, and 

 requires magnesium ions for maximal ac- 

 tivity. 



(4) Inorganic pyrophosphatase. Heppel 

 and Hilmoe (1951b) reported the presence 

 of an inorganic pyrophosphatase in bull 

 seminal plasma. The enzyme was not puri- 

 fied extensively, and it is not clear whether 

 it is different from other in'rophosphatases 

 in semen. 



(5) Nucleotide pyrophosphatases. The 

 enzymatic hydrolysis of adenosine triphos- 

 phate (ATP) by seminal plasma was ob- 

 served by Mann (1945) and by MacLeod 

 and Summerson (1946). Three distinct 

 ATPases were isolated from bull seminal 

 plasma by Heppel and Hilmoe (1953). The 

 first of these enzymes catalyzed the hy- 

 drolysis of ATP to inorganic pyrophosphate 

 and adenosine 5'-phosphate. The other two 

 catalyzed the liberation of inorganic ortho- 

 phosphate from ATP, and were active at 

 pH 5 and pH 8.5 respectively. The possible 

 identity of any of these proteins with other 

 enzymes which hydrolyze the pyrophos- 

 phate linkage of ]iyridine nucleotides (Wil- 

 liams-Ashman, Liao and Gotterer, 1958) 

 and cytidine diphosphate choline (Wil- 

 liams-Ashman and Banks, 1956) remains 

 to be established. 



The physiologic function of any of the 

 phosphatases in seminal plasma is un- 

 known. 



{6) Proteolytic enzymes. The proteolytic 

 activity of human semen was first noted by 

 Huggins and Neal (1942), and has been 

 studied extensively by Lundquist and his 

 collaborators. An enzyme similar to pep- 

 sinogen, and probably secreted by the semi- 

 nal vesicles, was discovered in human semi- 



