390 



PHYSIOLOGY OF GOXADS 



to remain at almost normal levels (Awapara, 

 1952b j. 



Seminal plasma and the secretions of the 

 male accessory glands contain a battery of 

 proteolytic enzymes [vide infra). For this 

 reason, changes in the levels of free amino 

 acids in these fluids resulting from hormonal 

 treatments should be interpreted with cau- 

 tion. Jacobbson (1950), for example, has 

 shown that in human semen, the nonprotein 

 nitrogen and amino-nitrogen content in- 

 creases many fold within 60 minutes after 

 ejaculation. 



Prostaglandin. A vasodepressor sub- 

 stance, designated j^rostaglandin, was found 

 by von Euler (1934, 1936) in the prostatic 

 and vesicular secretions of man, and also in 

 the accessory glands of sheep (von Euler, 

 1939). The prostaglandin of ram prostate 

 was i^urified by Bergstrom ( 1949), who sug- 

 gested that it was an unsaturated fatty acid 

 devoid of nitrogen. According to Eliasson 

 (1957), the prostaglandin of human semen 

 and of the prostate gland of sheep are iden- 

 tical. 



The pharmacologic effects which result 

 from the injection of seminal plasma icf. 

 Kurzrok and Lieb, 1931; von Euler, 1934, 

 1936, 1939; Goldblatt, 1935; Cockrill, Mil- 

 ler and Kurzrok, 1935; Asplund, 1947) are 

 complex, and are probably due to the com- 

 bined action of many constituents of this 

 fluid. The hypotensive action of protein 

 fractions of the secretions of some acces- 

 sory organs (Freund, Miles, Mill and Wil- 

 helm, 19581 is discussed below. 



Uric acid. Bull seminal vesicles may con- 

 tain as much as 70 mg. per cent of uric 

 acid (Leone, 1953). The uric acid content of 

 the semen of other animals is much lowci' 

 (Mann, 1954a). 



Urea. The urea content of human and 

 ram semen is much higlici' than that found 

 in the bull, boar, and stallion (Mann. 

 1954a). 



Major protein constitiiknts. Human 

 seminal plasma contains from 3.5 to 5.5 

 gm. of protein-like material per 100 niL 

 (Huggins, Scott and Heinen, 1942). Less 

 than 18 per cent of this material is coagu- 

 lable by heat, and as much as 68 per cent 

 of it is dialyzable. Thus the majority of 

 the seminal proteins of man can be classi- 

 fied as proteoses. Electrophoretic analyses 



of the nondialyzable proteins of human 

 seminal plasma have been performed by 

 Gray and Huggins ( 1942 1 and by Ross, 

 Moore and Aliller (1942). The major com- 

 ponents bore some correspondence to those 

 of blood serum, although the amount of 

 albumin was small. The proteins of bovine 

 seminal plasma are less dialyzable, and 

 more coagulable by heat, than those of man 

 (Larson and Salisbury, 1954). Electropho- 

 retic studies showed the presence of three 

 major and eight minor constituents, which 

 seemed to be distinct from the proteins of 

 bovine blood serum. In this species giyco- 

 or lipoproteins were present only in very 

 low concentrations. Larson, Gray and Salis- 

 bury (1954) found that the bovine seminal 

 plasma proteins are highly antigenic. They 

 obtained immunologic evidence that the 

 major protein constituents of this fluid are 

 distinct from any of the main ])rot(>ins of 

 either blood or milk. 



Enzymes, (i) Acid phosphatase. Kut- 

 scher and Wolbergs (1935) discovered that 

 human semen and prostate contain a very 

 active phosphatase which is optimally ac- 

 tive at pH 5 to 6. This enzyme is resjjonsi- 

 ble for the greater phosphatase activity of 

 male as compared with female urine. Its 

 secretion by the prostate accounts for the 

 fact that male urine collected from the 

 renal pelvis exhibits very little enzyme ac- 

 tivity (Scott and Huggins, 1942). Human 

 prostatic acid phosjihatase hydrolyzes a 

 number of phosphate monoesters (Kutscher 

 and Worner, 1936; Kutscher and Pany, 

 1938). The enzyme has been purified ex- 

 tensively (London and Hudson, 1953; Bo- 

 man, 1954; London, Sommer and Hudson, 

 1955). In addition to hydrolyzing phos- 

 phate esters, human prostatic acid phos- 

 phatase catalyzes the transfer of phosphate 

 from various donors to alcohols such as glu- 

 cose, fructose, and methanol (London and 

 Hudson, 1955; Jeffree, 1957). L-Tartrate 

 inliibits tlie enzyme competitively (Abul- 

 Kadl and King, ^1948). 



'I'hc activity of acid phosphatase in the 

 human jjrostate is low in childhood and in- 

 creases about 20 times at i)uberty (Gutman 

 and Gutman, 1938a). In adult men, the 

 acid phosphatase content of semen seems 

 to reflect the circulating levels of andro- 

 genic hoi-niones (Gutman and Gutman, 



