determination of effective dosage of fsh and hcg in

background: in vitro maturation (ivm) of oocytes reduces the costs and averts the side-effects of gonadotropin stimulation for in vitro fertilization (ivf). reliable ivm is an intellectual, scientific and clinical challenge with a number of potential applications. objective: the effect of hcg was evaluated on the timing and regulation of in vitro ovulation for the syrian mice oocytes in the presence and absence of fsh. materials and methods: preantral follicles, isolated from the ovaries of 6 weeks-old mice, were cultured in tcm-199 medium. the effect of 10-200 miu/ml fsh and 1.5 iu/ml hcg was seen on the follicle maturation, as well as the changes in ovulation capacity of enclosed oocytes, after the incubation period of 6 days at 37 °c, 92% humidity and 5% co2 in air. results: 100 miu/ml fsh showed increased follicle diameter, survival, germinal vesicle breakdown (gvbd) and oocyte maturation rates (p<0.0001). significantly higher number of follicles showed cumulus attachment when ovulation started within 16-24 hours post hcg (97% and 80% respectively; p<0.0001) as compared to the cultures without hcg or when the ovulation time increased from 24 hours post hcg. combination of fsh and hcg showed 97% (p<0.0001) ovulation as compared to that seen for fsh-containing medium only (81%) or control (10%). conclusion: the combined administration of 1.5 iu/ml hcg and 100 miu/ml fsh induces the in vitro follicle maturation, ovulation capacity and proper timing of mice oocytes.