Specific localization in the equatorial region of gp20, a 20 kDa sialylglycoprotein of the capacitated human spermatozoon acquired during epididymal transit which is necessary to penetrate zona-free hamster eggs.

In this study we set out to characterize gp20, a 20 kDa glycoprotein of the human sperm surface, first identified by us by radiolabelling the sialic acid residues of the sperm surface [R. Focarelli et al. (1995), Mol. Hum. Reprod., 2, 2755-2759]. The protein was partially purified from pooled sperm samples of several healthy donors and used to raise a specific antiserum to study its localization in the reproductive system. When tested with freshly ejaculated spermatozoa, the anti-gp20 antibody intensely stained the head and midpiece. However, on capacitated spermatozoa the antigen was restricted to a sharp zone in the equatorial region. The antibody did not bind to differentiating germ cells but the antigen was present in epididymal epithelial cells and also in seminal plasma. Anti-gp20 exerted a blocking effect in a test for sperm penetration of zona-free hamster eggs, thus suggesting that gp20 is involved in the early stages of fertilization.

[L-arginine and male infertility]. / L-arginina e infertilità maschile.

The clinical efficacy and acceptance of L-arginina HCL was tested in 40 infertile men. All of these men had a normal number of spermatozoa (> 20 million/ml), but a decreased motility; this decreased motility was not due to infection or to immunological disorders. The treatment consisted of 80 ml of 10% L-arginine HCL administered daily per os for 6 months. L-arginine HCL showed to be able to improve the motility of spermatozoa without any side-effects.