Identification of cholesta-7,24-dien-3 beta-ol and desmosterol in hamster cauda epididymal spermatozoa

The sterol composition of hamster cauda epididymal spermatozoa was remarkably different from that of several other mammalian spermatozoa. Desmosterol and cholesta-7,24-dien-3 beta-ol account for as much as 90% of the total sterols. Cholesterol and desmosterol are the major components of mouse cauda epididymal spermatozoa, and rabbit, boar and bull ejaculated spermatozoa. Cholesta-7,24-dien-3 beta-ol was not detected. Furthermore, Cholesterol was the main sterol in hamster caput epididymal spermatozoa, while only a trace amount of desmosterol was detected and cholesta-7,24-dien-3 beta-ol was hardly detected at all. The sterol content of cauda and caput epididymal spermatozoa was 0.17 +/- 0.05 mumol/10(8) spermatozoa. During maturation, the desmosterol and cholesta-7,24-dien-3 beta-ol levels increase and the Cholesterol level decreases. Cholesta-7,24-dien-3 beta-ol appears as a sterol in mature spermatozoa and seems to be a characteristic sterol of hamster cauda epididymal spermatozoa.