M. C. CHANG 123 



Hyaluronidase and Antihyaluronidase 

 in Mammalian Fertilization 



Hyaluronidase in relation to mammalian fertilization has been 

 reviewed by Chang (1950b) and Swyer (1951). According to 

 Mann (1954), the term hyaknonidase, in its widest sense, desig- 

 nates the mucolytic enzyme, or rather a gi'oup of enzymes which 

 bring about the depolymerization and hydrolysis of hyaluronic 

 acid. The mammalian testes and sperm are the richest animaj 

 sources of hyaluronidase. It is known that the hyaluronidase con- 

 tent in the semen is dependent on the concentration of sperm, 

 Swyer (1951) found that the hyaluronidase contents per 100 

 million spermatozoa per milliliter of semen of rabbit, bull, man, 

 and boar were approximately 20, 7, 0.4, and 0.2 units, respec- 

 tively, but only a very small amount of hyaluronidase, iiTespective 

 of the concentration of spermatozoa, could be detected in dog 

 semen. 



The recently ovulated rat or rabbit eggs are surrounded by a 

 viscous cumulus oophoris. Yamane (1935), Pincus and Enzmann 

 (1935) brought to light the fact that sperm suspensions or ex- 

 tracts of rabbit sperm could disperse the follicular cells of the 

 cumulus. McClean and Rowlands (1942) discovered that hy- 

 aluronidase obtained from testes, spermatozoa, snake venom, or 

 bacteria can act as a cumulus-dispersing factor by liquefying the 

 viscous gel which cements the follicular cells around freshly 

 ovulated rat eggs. Since the follicular cells surrounding the eggs 

 foiTii an obvious barrier for the penetration of the spermatozoon 

 into the egg, the role of hyaluronidase in mammalian fertilization 

 was very much stressed about ten years ago. Thus, addition of 

 hyaluronidase to rabbit sperm suspension was claimed to increase 

 the fertilizing capacity (Rowlands, 1944), and the application of 

 hyaluronidase for the treatment of human sterility was advocated 

 (Kurzrok et al, 1946; Kurzrok, 1950). 



It is known that a high concentration of hyaluronidase (Mc- 

 Clean and Rowlands, 1942) or a very high concentration of 

 spermatozoa, 20,000 per cubic millimeter (Pincus and Enzmann, 

 1936), is needed for the dispersal of follicular cells. This is not in 



