Are steroids obligatory mediators of luteinizing hormone/human chorionic gonadotropin-triggered resumption of meiosis in mammals?
Motola S; Popliker M; Tsafriri A Department of Biological Regulation, The Bernhard Zondek Hormone Research Laboratory, The Weizmann Institute of Science, Rehovot 76100, Israel. Steroids mediate the gonadotropic stimulus of oocyte maturation in fish and amphibians. Such a role of steroids in mammals has not been confirmed until recently. A series of studies presented data suggesting that steroids might be involved in meiosis of mouse oocytes. Here we examined this suggestion using in vitro cultures of rat and mouse follicle-enclosed oocytes (FEOs) and cumulus-enclosed oocytes (CEOs). In FEOs that mature only in response to gonadotropins or other stimuli, we tested the ability of steroids to trigger meiosis and whether addition of steroid receptor antagonists blocks LH/human chorionic gonadotropin stimulation of meiosis. In CEOs that mature spontaneously, we tested whether steroid antagonists block maturation and whether steroids overcome the inhibition of maturation by hypoxanthine (Hx)
