Fructose, a Constituent of Semen

Abstract

BULL spermatozoa separated by centrifugation and washing from the seminal plasma can survive anærobically only if some glycolysable carbohydrate is added¹ ; they can utilize glucose, fructose and mannose but not glycogen. In the whole semen, on the other hand, the spermatozoa survive without any additional sugar and they live at the expense of a reducing carbohydrate already present in the seminal plasma. Hitherto, this carbohydrate has been regarded as glucose². However, in view of the inadequate evidence as to the identity of the sugar, an investigation of its chemical nature was undertaken. It revealed that the greatest part of the reducing sugar content of the seminal plasma is derived not from glucose but from fructose. From 120 ml. of bull semen, on purification, 15 ml. of a solution were obtained in which both the optical activity and the reducing value were determined and found to correspond to 630 mgm. fructose. Fructose was also identified as crystalline methylphenyl-fructosazone³. In small samples of semen (0.1 ml.) it was found possible to estimate fructose quantitatively by an adaptation of the method of Roe⁴; the analysis of seven freshly collected samples of bull semen gave the following results.