ACTION OF PHILEOMYCIN ON MEIOSIS OF MOUSE OVUM

A study of the in vivo and in vitro effects of phleomycin on meiosis of the mouse egg revealed a spectrum of damage to both first metaphase and second metaphase with polar body. The minimal effective dose in vivo of 2.5 μg per g of body weight altered 28.3% of first metaphase figures and 50% of second metaphase cells. Damaged ova were, nevertheless, capable of forming a polar body and a second metaphase figure as well as escaping from the follicle. In vitro, a minimum concentration of 10-3 mC per ml of media damaged 6.6% of first metaphase figures and 92% of second metaphase figures. In both systems much greater doses produced severe damage which totally interfered with meiosis and abstriction of the first polar body. Some implications concerning the interaction of nuclear meiosis and the unfolding of the process of ovulation are noted. © 1968.