mid-gestation rat conceptuses were cultured for 48 h in serum containing the retinoids all-trans-retinoic acid ( tra ) , 13-cis-retinoic acid ( 13-cra ) , etretinate ( etr ) , etretin or one of six retinamides at concentrations ranging from 0.5 to 400 micrograms/ml .
C0032961
gestation
C0022265
13-cra