1971 Volume 11 Issue 2 Pages 59-65
Nulliparous female mice of ICR-JCL strain, 4-75 weeks old, and supplied by Japan CLEA Co. , Ltd. , were mated with mature male mice of the same strain. Pregnant females were injected with 25 mg/kg/day of prednisolone, suspended in CMC, subcutaneously for four consecutive days beginning on day 11 of pregnancy, and put to death on day 18 of pregnancy. Percentage of fetal loss with females treated was higher than among control females in all age groups except those older than 52 weeks. Analysis of multiple regression for incidence of cleft palate revealed that there were two phases, namely, a first higher phase from 4 to 23 weeks of age, and a second lower phase from 24 to 75 weeks of age. In age groups older than 24 weeks, incidence of cleft palate decreased according to age. Average body weight of live fetuses was lower in groups treated of any age. There was no characteristic relationship between the incidence of cleft palate and lit ter size or maternal body weight in the group treated of any age.