Volume 2 Issue 2, July 1992: 103-117
ORIGINAL ARTICLES
Studies on the physiological function of spermine in the process of progesterone induced toad oocyte maturation
Runsheng Li and Jiake Tso
Shanghai Institute of Cell Biology, Academia Sinica
Correspondence:
Spermidine or spermine but not putrescine inhibited progesterone induced Bufo bufo gargarizans oocyte maturation. The ID50 for spermine inhibition via intra - oocyte microinjection on maturation induced by progesterone was 6. 8 mM(100 nl). Spermine could inhibit MPF induced toad oocyte maturation with a much higher ID50.
A 55 kD protein was dephosphorylated during the process of progesterone induced oocyte maturation. Spermine selectively promoted the level of phosphorylation, of this protein in both progesterone- stimulated and hormone- untreated oocytes. The extent of its dephosphorylation was fairly correlated with the percentage of GVBD in the hormone stimulated oocytes.
The level of endogenous spermine was reduced by 28% between the period of 0. 40 GVBD50 and 0. 60 GVBD50, at which 55 kD protein was dephosphorylated.
Spermine inhibited progesterone- stimulated protein synthesis in almost the same dose dependent manner as its inhibitory effect on the hormone- induced maturation. The endogenous spermine regulated 55 kD protein dephosphorylation which may trigger the increase of protein synthesis and in turn promote the activation of MPF. It is possible that 55 kD protein may be one of the components of messenger ribonucleoprotein (mRNP) particles.
Cell Res 2: 103-117; doi:10.1038/cr.1992.11
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