190 The Biochemistry of Semen 



Fleury and Balatre (1947) and in the reports by Courtois, Fleury, 

 Posternak, and Schopfer, forming part of a (1951) symposium. 



Inositol as a major constituent of the seminal vesicle secretion in the 

 boar 



In 1951, in the course of investigations on ergothioneine, the 

 author noticed that a large ethanol-precipitable fraction could be 

 separated from the boar vesicular secretion, containing no ergo- 

 thioneine, citric acid, or fructose, and almost free from sulphur, 

 nitrogen, or phosphorus. On further purification, from 1 litre of 

 the vesicular secretion, 18 g. of crystalline material was obtained 

 which had a pronounced sweet taste, but was non-reducing and 

 optically inactive. The substance had a m.p. of 225° which is that 

 of pure m^'^cinositol, and contained 40-28 °o carbon and 6-79% 

 hydrogen, as against 40-ll°o carbon and 6-66% hydrogen, theoreti- 

 cally expected from inositol. The Scherer-Salkowski reaction per- 

 formed with 01 mg. was strongly positive, and on oxidation with 

 periodic acid the substance isolated from the seminal vesicle secretion 

 showed a titration curve identical with that of pure mesomo?,\Xo\. 



This and subsequent experiments (Mann, 1951c, 1954) showed 

 that the boar vesicular secretion is the richest source of free 

 inositol in nature, and that between 40 and 70% of the dialysable 

 contents of this biological fluid is made up of inositol. Table 25 

 shows the results of chemical analyses of the vesicular secretion 

 from five boars, carried out in each instance on fluids collected 

 separately from the left and right gland. As can be seen, the 

 inositol content of these fluids was 208 to 2-64%, the variations 

 being much smaller than they would be in the case of fructose or 

 citric acid. It is also of some interest to note that the left and the 

 right seminal vesicle produced secretory fluids which were alike in 

 quantitative composition. The average values (mg./lOO ml.) based 

 on the analyses of five pairs of secretions were: fructose 65, citric 

 acid 381, ergothioneine 91, inositol 2414. 



Inositol is restricted in its distribution to the seminal vesicle, and 

 is not present, at any rate in appreciable quantities, in the secretions 

 from the boar epididymis or Cowper's gland. Furthermore, it 

 appears to be rather specific for the boar, so far as can be judged 

 from preliminary experiments carried out with the semen of other 



