IMPROVEMENT OF MOTILITY AND FERTILIZATION POTENTIAL OF POSTTHAW HUMANSPERM USING GLUTAMINE

The effectiveness of three amino acids, glutamine, proline, and histid ine, and one amino acid-related compound, betaine, in preserving human sperm diluted v/v in a basal medium (BM) containing 14% glycerol duri ng the freeze-thaw (FT) process was studied. At 80 mM in BM, only glut amine improved the 5- to 60-min postthaw total and progressive motilit ies and velocity. The presence of glutamine at 80 mM is not sufficient to achieve lower concentrations of the toxic agent glycerol in FT med ium. Glutamine may therefore have a mechanism of protection on human s permatozoa that is independent from that of glycerol. The zona-free ha mster egg penetration test showed that the percentage of eggs penetrat ed was significantly greater when spermatozoa were frozen-thawed with 80 mM glutamine in BM. Consequently, the presence of glutamine at 80 m M in a glycerol-FT medium maintains human sperm motility and fertilizi ng ability during the FT process. (C) 1996 Academic Press, Inc.