ATP‐γ‐S (adenosine 5′‐0(3‐thiotriphosphate)) blocks progesterone‐induced maturation of the Xenopus oocyte

Abstract

ATP‐γ‐S microinjection into Xenopus oocyte prevents progesterone induced maturation. Inhibition is time and dose dependent; 50% inhibition occurs when 50 nl of 0.5 mM ATP‐γ‐S solution are microinjected/oocyte 1 hr prior to the hormonal trigger. ATP‐γ‐S inhibited oocytes can be induced to mature (100%) following microinjection of extracts containing maturation promoting factor (MPF). Our results suggest that the maturation protein(s) has been stabilized in ovo by ATP‐γ‐S microinjection, in its phosphorylated inhibitory form.