EFFECT OF SPERM PRETREATMENTS ON THE RESULTS OF SUBZONAL INSEMINATION(SUZI)

Follicular fluid and progesterone, which are present in the natural en vironment of oocytes, have been reported to induce the acrosome reacti on and we compared their use in pretreatment of spermatozoa for human sub-zonal insemination (SUZI). Pre-treatment with follicular fluid (20 % v/v) was associated with a higher fertilization rate than pre-incuba tion with progesterone (1 mmol/l) as assessed by both the embryos/ inj ected oocytes rate (31.7 +/- 6.2% versus 13.5 +/- 5.9%, respectively; P < 0.01) and the male pronuclei/injected spermatozoon rate (10.5 +/- 3.3% versus 3.6 +/- 1.9%, respectively; P < 0.01). Since we have previ ously reported that pre-treatment with progesterone allowed a higher p ercentage of live-reacted spermatozoa to be obtained, these results su ggest that either progesterone induces modifications of the plasma mem brane, which prevent fusion with the oolema, or that follicular fluid not only induces the acrosome reaction but increases the fusion abilit y by compounds other than progesterone.