Protein Constituents and Enzymes of Seminal Plasma 119 



A similar relation to age was observed in monkeys and dogs; in 

 both these species administration of androgenic hormones to imma- 

 ture males stimulates considerably the output of the enzyme from 

 the prostate gland (Gutman and Gutman, 1939; Huggins and 

 Russell, 1946). A certain correlation appears to exist in adult men 

 between the level of acid phosphatase in semen and androgenic 

 activity (Gutman and Gutman, 1940; Gutman, 1942; Engberg, 

 Anderson, Sury and Raft, 1947). However, like other constituents 

 of semen, the level of prostatic phosphatase activity varies from one 

 species to another, as well as between individuals within the same 

 species. 



Under physiological conditions, acid phosphatase does not pass 

 from the prostate into the blood stream. However, significant 

 amounts of it appear in the blood plasma as a result of malignant 

 growth in the prostate and metastases of prostatic cancer in the 

 bones; injections of androgen still further increase the level of 

 enzyme in blood plasma, whereas castration or treatment with 

 oestrogens lead to a spectacular decrease. The determination of 

 prostatic phosphatase activity in blood has been utilized as a valuable 

 diagnostic aid in prostatic carcinoma and in the course of clinical 

 treatment (Gutman and Gutman, 1938a; Huggins, Scott and Hodges, 

 1941; Watkinson, Delory, King and Haddow, 1944). 



An important addition to our knowledge of the physiological 

 functions of acid phosphatase in seminal plasma, has been the dis- 

 covery made by Lundquist (1946) that freshly ejaculated human 

 semen contains phosphorylcholine which on ejaculation is rapidly 

 dephosphorylated by the acid phosphatase to free choline and 

 orthophosphate. This phenomenon is more fully discussed else- 

 where (p. 170). But there is evidence that apart from the acid phos- 

 phatase which acts on phosphorylcholine optimally at pH 6-3 (in 

 acetate buffer), human seminal plasma contains another phosphatase 

 which acts on the same substrate at a higher pH (Hudson and Butler, 

 1950). Of considerable interest is also the finding that the acid 

 seminal phosphatase exhibits in vitro a distinct transferase activity 

 (Green and Meyerhof, 1952); partially purified acid phosphatase 

 from the human prostate has been shown to catalyse at pH 5-5 

 the transfer of phosphate from both ^S-phosphoglycerol and phospho- 

 creatine to glucose; the product in each case was 6-phosphoglucose 



