Digital anomalies in the embryonic mouse limb cultured in the presence of excess vitamin A.

Forelimb buds of days 10 to 12 ICR/JCL mouse embryos were cultured on a liquid medium consisting of 90% Eagle's MEM and 10% fetal calf serum. Experimental explants were exposed to retinol (10 iu/ml) for the first 24 hours of culturing. In the control explants, chondrified metacarpals and proximal phalanges increased in number as the age of the donor limb bud increased. All treated explants cultured on the experimental medium showed abnormal development compared with the controls. Lesions caused by vitamin A shifted from proximal to distal limb segments as the age of donor limb bud increased.