Timing of meiotic stages in oocytes of the Syrian hamster (Mesocricetus auratus) and analysis of induced chromosome aberrations.

The stages of maturation of oocytes (meiotic stages) in adult Syrian hamsters (Mesocricetus auratus) have been timed following superovulation treatment. Timing and superovulation were induced by an injection of pregnant mares' serum on the first morning of the estrus cycle, followed by injection of human chorionic gonadotropin (HCG) in the evening of the fourth day. The oocytes completed the prophase of the first maturation division 3 h after the injection of HCG. Ovulation began 9 1/2 h after the injection. A method of analysis of metaphase II chromosomes of Syrian hamster oocytes 16 h after injection of HCG is described. This method seems to be appropriate for the examination of the induction of genetic defects during oogenesis. Female hamsters were treated with 2,3,5-triethyleneimonobenzoquione-1,4. The induced chromosome aberrations were analysed. Dosis-dependent response could be demonstrated.