[The occurrence rate of neonatal anomaly related to aging of grafted ovaries in mice (author's transl)].

An increase in the birth rate of malformed neonates with the aging of mothers has recently become clear. No studies, however, have been made as to whether such frequent occurrence of anomalies does depend on "the aging of ovaries", as has generally been assumed. The authors, in an attempt to elucidate the above mentioned basic subject, studied the relationship between the aging of ovaries and the occurrence rate of malformed newborn experimentally with C57BL/6J strain mice by grafting young castrated female mice orthotopically with different aged ovaries, from young to old, and mating them with young males. As controls, non-treated different aged females were mated with young fixed age males. The frequency in the birth of malformed mice in both the experimental group and the control group were examined and compared. As the age exceeded 400 days, the occurrence rate of anomaly rose sharply in the non-treated natural controls. When the grafted ovarian age exceeded 400 days, exactly the same result was obtained in the experimental group which showed a high incidence of neonatal anomaly. The results obtained above have suggested to us for the first time that the frequent occurrence of neonatal anomalies related to maternal aging is influenced strongly by the ovarian aging, but not by the aging of the other organs in the mother mice.