Similar responsiveness between C57BL/6N and C57BL/6J mouse substrains to superovulation.

Superovulation is a method for the drug-induced release of multiple eggs and useful for in vitro fertilization. Thus, its high efficiency largely reduces the number of mice used per experiment. We compared the responsivity to superovulation between C57BL/6N (B6N) and C57BL/6J (B6J) substrains. The average number of ovulated eggs was strikingly higher in both substrains treated with anti-inhibin serum (AIS) plus equine chorionic gonadotropin (eCG) than those treated with eCG alone. Our data indicate that hypothalamus-pituitary-ovarian axis similarly responds to eCG treatment in B6N and B6J mice, and that this responsiveness is enhanced by the presence of AIS.