Elevated tissue type plasminogen activator in human granulosa cells correlates with fertilizing capacity

An increased production of plasminogen activators, able to convertplasminogen into plasmin, has been found in experiments in vivoon rat ovarian granulom cells at the time of ovulation, indicatingan involvement in follicular rupture. The graoulosa cells of49 follicles from 20 patients undergoing in-vitro fertilizationwere obtained by laparclscopy and tested for the content ofurokinase-type plasminogen activator (u-PA), tissue-type plasminogenactivator (t-PA) and inhibitor of plasmhogen activator (PAI).In the respective follicular fluids the concentrations of oestradiol(E₂), progesterone (P) and testosterone (T) were determinedand the levels of these enzymes and of the follicular steroidcontent were related to the fertilizing behaviour of the respectiveoacytes. Follicles containing oocytes which could be fertilized,revealed significantly higher follicular fluid E₂ and P levelsand significantly lower T levels than follicles with unfertilizedoocytes. The respective granulosa cells of fertilized oocytesexhibited higher levels of t-PA compared to their unfertilizedcounterparts, whereas no significant difference occurred inthe levels of u-PA and PAI. These data suggest that successfulfertilization of human oocytes is associated with a high contentof t-PA in granulom cells and high E₂ and P levels in the follicularfluid.