TAURINE AND HYPOTAURINE: THEIR EFFECTS ON MOTILITY, CAPACITATION AND THE ACROSOME REACTION OF HAMSTER SPERM IN VITRO AND THEIR PRESENCE IN SPERM AND REPRODUCTIVE TRACT FLUIDS OF SEVERAL MAMMALS*

Abstract

Previously it was shown that the .beta.-amino acid taurine can support and stimulate hamster sperm motility during in vitro capacitation in the presence or absence of epinephrine. In vitro results are described here which demonstrate that hypotaurine, a precursor of taurine, can also support and stimulate motility under these conditions, and that a higher number of acrosome reactions occur in the presence of taurine as compared to hypotaurine (both in the presence and absence of epinephrine). In all cases, the greatest percentage of acrosome reactions occurs in the presence of epinephrine. Whether these .beta.-amino acids act independently of epinephrine or in a synergistic manner with it remains to be determined. Hypotaurine and taurine are present at high levels in bovine follicular fluid, rabbit uterine and ampullar oviductal fluid (11 h after mating, i.e., 1 h after ovulation), monkey oviductal fluid, bovine adrenal cortex motility factor preparation and human, guinea pig and hamster sperm preparations. Taurine and hypotaurine may possibly have roles in vivo in the maintenance and stimulation of sperm motility, and stimulation of capacitation and/or acrosome reactions.