Glycolipid composition of human testis at different ages and the stereochemical configuration of seminolipid.

1. The sterochemical configuration of glycerol moiety of seminolipid (1-O-alkyl-2-O-beta-D-(3'-sulfo) galactopyranosylglycerol: Ishizuka, I., Suzuki, A. and Yamakawa, T. (1973). J. Biochem. 73, 77--87) from mammalian testis was determined by measurement of optical rotatory dispersion of alkylglyceryl ether moiety, establishing the final structure of the major glycolipid from mature testis of mammals as 1-O-alkyl-2-O-beta-D-(3'-sulfo)-galactopyranosyl-sn-glycerol. 2. The simple and sensitive modification of fluorometric determination of galactolipids and sphingolipids was described. This method does not require lipid extraction from silica gel of thin-layer chromatography, and allows a quantitative assessment of the sphingoglycolipids and galactosyl glycerides using a small amount of testicular tissue. 3. Various lipid classes from human testis of varying age groups were compared. The total lipid and seminolipid content was highest in adult (40-years-old) testis amounting to 39.0 mg and 158.7 nmol/g tissue, respectively. Seminolipid was not detected in infant (2 years old) or child (9 years old) and found only at the concentration of 25.3 nmol/g in the testis of aged (60--90 years of age) supporting the postulated relation of seminolipid with spermatogenesis and sexual activity. In contrast, ganglioside content was highest in the testis of aged probably reflecting fibrosis of the testis. The main ganglioside was found to be hematoside with N-acetylneuraminic acid. Gangliosides Gm1 and GD1a were also detected.