Fructose and Fructolysis 139 



Seminal fructose as an indicator of male sex hormone activity; the 

 'fructose test^ and its application to certain problems of sex 

 endocrinology 



The 'fructose test', originally described by Mann and Parsons 

 (1947) and subsequently developed by Mann, Davies and Hum- 

 phrey (1949), Mann, Lutwak-Mann and Price (1948) and Mann 

 and Parsons (1950), is founded on the observation that the capacity 

 of the accessory organs to produce fructose and, thereby, the actual 

 level of fructose in the seminal plasma, reflects in a faithful manner 

 the degree of testicular hormone activity in the male, and in this 

 way provides an accurate indicator of endocrine testicular function. 

 In experiments on rats and rabbits it was shown that seminal fruc- 

 tose disappears almost completely within two weeks after castration 

 and also that the postcastrate fall in the level of fructose can be 

 prevented, or, if already developed, fully restored, by the implan- 

 tation of testosterone (Fig. 12). The effect is not limited to labora- 

 tory animals and analogous results were obtained with domestic 

 animals such as the bull. 



The test can be carried out in two ways, by the chemical analy- 

 sis of the seminal fluid collected from an intact animal by means 

 of an artificial vagina, or by the analysis of accessory organs of 

 reproduction obtained from the experimental animal by dissection. 

 The first method gives an opportunity to observe in the same animal 

 the time-sequence of changes brought about by castration and hor- 

 monal treatment, and eliminates the sacrifice of the experimental 

 animal. In the second procedure, on the other hand, the test can 

 be used for a quantitative assay of male sex hormone activity in the 

 whole body, isolated tissues, body fluids and hormone preparations; 

 as an illustration. Fig. 13 gives a dosage-response curve obtained 

 with coagulating glands of castrated rats which were injected for 

 three weeks with known doses of testosterone propionate; following 

 the last day of injections the rats were sacrificed, the coagulating 

 glands dissected and used for fructose analysis. 



Below are discussed some of the endocrinological problems to 

 which an approach was made in recent years with the aid of the 

 'fructose test', applied either alone or in conjunction with the 'citric 

 acid test', which depends on the relationship between the secretion 



