ACCESSORY MAMMALIAN REPRODUCTIVE GLANDS 



389 



tivity of various hormones (Mann and Par- 

 sons, 1950; Price, Mann and Lutwak-JMann, 

 1955; Ortiz, Price, Williams-Ashman and 

 Banks, 1956), and the effect of nutrition on 

 the onset of androgen secretion and sperm 

 formation in bull calves (Davies, Mann and 

 Rowson, 1957). 



The androgen-induced changes in the cit- 

 rate levels in semen and various accessory 

 glands are reminiscent of similar alterations 

 in the fructose content of these tissues. How- 

 ever, the concentrations of these substances 

 do not necessarily parallel one another in re- 

 sponse to hormonal stimulation. In the post- 

 castrate animal, the fall in citric acid and its 

 reappearance after androgen treatment is 

 usually more sluggish than that of fructose. 

 Also, the seminal fructose of some species 

 may not be secreted by the same accessory 

 organ (or lobes of the gland ) which produces 

 citric acid. Thus in the rat, fructose is se- 

 creted by the anterior and dorsolateral pros- 

 tate, whereas citric acid is derived from the 

 seminal vesicles and dorsolateral and ven- 

 tral prostates, but is totally absent from the 

 anterior prostate (Humphrey and Mann, 

 1949). In the guinea pig, however, the semi- 

 nal vesicles are the principal source of both 

 fructose and citric acid (Ortiz, Price, Wil- 

 liams-Ashman and Banks, 1956). 



Using a strain of rats in which the inci- 

 dence of the female prostate is very high, 

 Price, ]Mann and Lutwak-JVIann (1949) 

 showed that the growth of this gland which 

 follows the injection of testosterone is ac- 

 companied by a tremendous increase in its 

 content of citric acid. In this way the female 

 prostate resembles the ventral prostate gland 

 of the male rat. 



Citric acid is synthesized in the i)rostate 

 gland by the usual reactions of the tricar- 

 boxylic acid cycle (Williams-Ashman, 1954; 

 Williams-Ashman and Banks, 1954b). No 

 other organic acids are present in more than 

 trace amounts in the secretions of those ac- 

 cessory glands that accumulate citrate. The 

 enzymatic machinery for the degradation of 

 citric acid via the tricarboxylic acid cycle is 

 jH-esent in the rat ventral prostate gland 

 OVilliams-Ashman, 1954; Williams-Ashman 

 and Banks, 1954b; Williams-Ashman, 1955) 

 and there is no evidence, despite suggestions 

 to the contrary (Awapara, 1952a), that cit- 



ric acid accumulates because it cannot be 

 oxidized. It has been suggested that a com- 

 mon denominator affecting the androgen- 

 dependent accumulation of citric acid and 

 fructose in the accessory glands is the intra- 

 cellular balance between the oxidized and 

 reduced forms of DPN and TPN (Talalay 

 and Williams-Ashman, 1958). 



^lann (1954a) has summarized the ideas 

 of various authors concerning the possible 

 functional role of citric acid in seminal 

 plasma. All of these suggestions are based 

 more upon conjecture than experimental 

 fact. 



Catecholamine^. There is evidence for the 

 presence of both epinephrine and norepi- 

 nephrine in seminal pla.sraa (Brochart, 1948; 

 Beauvallet and Brochart, 1949). Extracts of 

 human prostate and seminal vesicle contain 

 a monoamine oxidase which oxidizes cate- 

 cholamines (Zcller and Joel, 1941). Katsh 

 (1959) detected serotonin and histamine in 

 human ejaculates. 



Amino acids. Chromatographic studies 

 have revealed the presence of many free 

 amino acids in human semen (Jacobbson, 

 1950; Lundquist, 1952), from which crystal- 

 line tyrosine was isolated by Wagner- 

 Jauregg (1941). According to Barron and 

 Huggins (1946b), human prostatic adenoma 

 is very rich in free glutamic acid, and the 

 nonprotein amino-nitrogen of this and dog 

 prostatic tissue is high. Bovine seminal 

 plasma contains free serine, alanine, glycine, 

 and aspartic and glutamic acids (Gassner 

 and Hopwood, 1952). A similar distribution 

 of amino acids is found in the vesicular and 

 ampullary secretions of the bull. The free 

 amino acid levels of bull seminal plasma fall 

 greatly after castration. In the rat, Marvin 

 and Awapara (1949) found that the concen- 

 tration of free amino acids in the whole pros- 

 tate decreased markedly following orchidec- 

 tomy, and could be restored to normal levels 

 in the castrate animal by treatment with 

 androgen. In this species, Awapara (1952a) 

 observed that the content of free amino acids 

 in the ventral lobe of the prostate was much 

 higher than in the dorsal lobe. After castra- 

 tion, there was a marked drop in the content 

 of most amino acids with the exception of 

 aspartic and glutamic acids, which seemed 



