The present study was examined to clarify the role of calcium ion as a factor for the maturation of mouse oocytes.
Follicles and cumulus-enclosed oocytes were isolated with two sharp needles under a stereomicroscope from female mouse (ICR) ovaries which were treated PMSG 5IU 45-46 hours previously.
Isolated follicles and cumulus-enclosed oocytes were cultured for 14-16 hours in an organ culture system at 37℃, 5% CO2 in air and 100% humudified in incubator.
MHBS was the basic medium used from which A23187, verapamil, NiCl2. 6H2O and LaCl3. 7H2O were added depending on the experimental groups. In follicle- or cumulus-enclosed oocytes were cultured in these differently treated media.
@ES Following results were obtained from the present study.
@EN 1. The calcium ionophore A23187 directly or indirectly seems to stimulate GVBD of follicle-enclosed mouse oocytes. Increasing concentration of ionophore A23187 1ed to an increase in oocytes degeneration from the cumulus-enclosed oocytes.
2. The organic Ca++ channel blocker, verapamil does not induce GVBD of follicle-enclosed mouse oocytes. Specially, higher dose of 1mM verapamil induced GVBD of follicle-enclosed mouse oocytes. However, cytoplasm of GVBD oocytes in 1mM verapamil
treated
groups appeared shrunk. In the cumulus-enclosed oocytes, polar body formation was reduced in verapamil treated groups and degeneration increased.
Verapamil inhibit oocvte maturation (polar body formation).
3. The Ca++ inhibitor, Nickel (NiCl2. 6H2O) inhibits maturation of the follicle-enclosed oocytes. IN the cumulus-enclosed oocytes the progression to MII (PB formation) was reduced and degeneration of mouse oocytes increased as the concentration
of
Ni++
increase.
4. The Ca++ inhibitors, Lanthanum (LaCl3. 7H2O) has shown different effect from that of nickel. In follicle-enclosed oocytes, 0.01mM lanthanum induced maturation of mouse oocytes. Polar body formation was reduced in the cumulus-enclosed oocytes
all
lanthanum treated group.
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