A COMPARATIVE STUDY OF PA ACTIVITY OF RAT OVARAIN FOLLICLES AND THE EFFECT OF GONADOTROPINS
Chang Shi-ming and Xu He-sheng (Shanghai Institute of Cell Biology,Academia Sinia)
The main aim of this work is to observethe relative activity of plasminogen activator(PA) produced by ovarian granulosa cells indifferent stages of the development of folli-eles and the regulation of PMSG and HCG. Immature female Wistar rats of age 26days were induced by PMSG and/or HCG,and PA activites were measured by means ofdetermining the radio activity of fibrinolyticfragments degradated from (125)~I-fibrin.Theexprimental results consist of three parts: 1.Rats induced with PMSG for 48 hr,then followed by HCG for 8—10 hr,posses-sed preovulatory follicles (dia.0.8—l.1mm)and follicles in size (dia.0.4—0.8mm).Granulosa cells of the former showed a signi-ficant PA activity than that of the latter. 2.Granulosa cells either derived fromrats treated with PMSG or from rats notprimed by this hormone were incubated inthe medium containing HCG of various con-centrations (25x10~(-8)-25x10~(-2)I.U.).ThePA activity in cells from the PMSG primedrats kept a linear increase,the maximalamount was achieved at the concentration25x10~(-2)I.U.,whereas only a slight increasewas noted in cells from rats which did notreceive PMSG in vivo prior to the treatmentwith HCG in vitro. 3.Granulosa cells obtained from PMSGprimed rats were cultured with HCG at aconcentration 25x10~(-2)I.U.,The bormonaeffect to the production of PA was time de-pendent,the PA activity was related withthe duration of responsive time,but it wasno longer increased after 24 hr. Taken together,the PA activity is wellcorrelated with the development of ovarianfollicle,it shows the most significant activityin preovulatory stage,and it is regulated bythe PMSG and HCG.