Creatine and Creatinine 179 



35S-labelled ergothioneine was fed to the boar, some of it was ex- 

 creted, unchanged, in the semen. This provides interesting evidence 

 of the passage into semen of a substance absorbed from the ali- 

 mentary tract. 



Since ordinary fodder contains no ergothioneine, there remained 

 the possibiUty of its microbial formation in the digestive tract. 

 This, however, was not borne out by an experiment in which 

 aureomycin was fed to a boar, 1 g. daily for 24 days, but did not 

 affect in any way the level of ergothioneine in semen. 



Human semen, and that of certain other mammals so far inves- 

 tigated, was found to contain only a trace or no ergothioneine. In 

 the bull, ram, and in man, the considerable reducing power of the 

 seminal plasma towards dichlorophenol-indophenol is derived partly 

 from ascorbic acid, but partly also from other reducing substances 

 which await proper identification (Mann and Leone, 1953). An 

 interesting approach in this direction was made by Larson and 

 SaHsbury (1952, 1953) who reported on the presence in bull semen 

 of an as yet unidentified reducing substance characterized by a 

 positive reaction with sodium nitroprusside, and of sulphite. 



CREATINE AND CREATININE 



Occurrence in mammalian semen, and in the sperm and gonads of 

 invertebrates 



One of the earliest references to the presence of creatine and 

 creatinine in male reproductive organs is to be found in a paper by 

 Treskin who in Hoppe-Seyler's laboratory in 1872, isolated 016 g. 

 pure creatinine from two pairs of bull testes. In 1923, Steudel and 

 Suzuki isolated large quantities of crystalline creatinine, together 

 with another nitrogenous base, namely agmatine, from ripe, fresh 

 testicles of herring. Ilyasov (1933), using the colorimetric method 



/NHx 

 /NH. / \ 



HN=:C COOH HN=C C=0 



I " I 



CH3 CH3 



Creatine Creatinine 



13 



