INFLUENCE OF MEDIA AND THERMAL-SHOCK ON SPERM CAPACITATION

To elucidate the influence of medium and thermal shock in inducing spe rm capacitation, eight ejaculates were processed as follows. Each ejac ulate was divided into three aliquots. To two of tile aliquots, an equ al volume of saline was added, while TEST-yolk was added to the remain ing aliquot. All three samples were cooled slowly to 5 degrees C and i ncubated for 18-20 h. After aspirating the supernatant, 6 mi of Tyrode solution containing 0.06 g% egg yolk, warmed to 37 degrees C was adde d ss without disturbing the sperm pellet to the aliquot containing TES T-yolk and to one of the aliquots mixed with saline. To the remaining saline-processed sperm pellet, 6 ml TEST-yolk (37 degrees C) was added . AU samples were washed twice (400 x g for 5 min) and processed for t he sperm penetration assay (SPA). Samples, either pre-incubated in TES T-yolk (mean+/-SEM; 65.9+/-11.7%) or warmed (thermal shock) with TEST- yell; (62.6+/-12.1%)) yielded significantly (P<0.05) higher SPA outcom e than the samples processed and warmed with saline (17.8+/-12.0%). Th e penetration indices were not statistically different from each other . It therefore appears that the medium influences the sperm capacitati on process to a greater extent and may augment the influence of therma l shock.