68 The Biochemistry of Semen 



Of recent years the introduction of biochemical methods made it 

 practicable to follow up and to assess androgenic or gonadotrophic 

 activity, or changes due to hormonal deficiency, by means of quanti- 

 tative chemical analysis of the seminal plasma. Determinations of 

 fructose, citric acid and phosphatase activity in semen provide excel- 

 lent evidence of the functional state of the male accessory organs of 

 reproduction. These methods which will be discussed in detail later, 

 are particularly useful in studies of progressive hormonal deficiency, 

 such as is brought about for instance, by defective nutrition. The 

 great advantage of the chemical approach is that it enables the 

 assay of accessory gland function to be carried out in live animals, 

 at selected intervals, and over long periods of time. 



So far, there has been little progress in investigations concerning 

 the influence of hormones on semen in vitro. Several hormones have 

 been variously credited with beneficial effects upon the survival, 

 motility and metabolism of sperm in vitro (cf. Tschumi, 1946), but 

 in actual fact, apart from isolated observations such as those 

 concerning the stimulating effect of thyroxine on spermatozoa 

 (Carter, 1931, 1932; Lardy and Phillips, 1943^; Schultze and Davis, 

 1948, 1949; Maqsood, 1952), the evidence at hand requires much 

 strengthening before the various claims are accepted as valid. The 

 same is true of studies on the content of hormones in semen itself. 

 There are indications that semen contains some oestrogenic sub- 

 stances (Green- Army tage et al., 1947; McCullagh and Schaffenburg, 

 1951; Mukherjee et al., 1951) which is not improbable since oestro- 

 genic hormones occur elsewhere in the male body, notably in the 

 testis and in the urine. Diczfalusy (1954) examined by counter- 

 current distribution and fluorimetric analysis an alcoholic extract 

 from a litre of human semen and found in this material 10 fig. of 

 oestradiol-lT/S, 30 jug. oestriol, and 60 jug. oestrone, all in a free 

 non-conjugated form. 



With respect to androgens, the Dirscherl-Zilliken colour reaction 

 for dehydro/56>androsterone is strongly positive in extracts from 

 hydrolysed spermatozoa. According to Dirscherl and Kniichel 

 (1950), the content of the colour-yielding material corresponds to 

 about 5-5 mg. 'dehydroandrosterone' in 100 ml. human semen, as 

 compared with 0-1 mg./lOO ml. in human urine; for bull and stallion 

 semen the values are given as 4-3 and 1-6 mg./lOO ml., respectively. 



