 techniques for isolation and culture of fetal type ii alveolar epithelial cells , as well as the morphologic and biochemical characteristics of these histotypic cultures , are described . 
 type ii alveolar epithelial cells can be isolated from fetal rat lungs and grown in an organotypic culture system as described in this review . 
 the fetal type ii cells resemble differentiated rat type ii cells in morphology , biochemistry , and karyotype as they grow in culture for up to 5 weeks . 
 the cells of the mature organotypic cultures form alveolarlike structures while growing on a gelatin sponge matrix . the type ii cells also synthesize and secrete pulmonary surfactant similar in biochemical composition to that produced in vivo . this system has been used to study the effects of hormones on surfactant production and composition . 
 the organotypic model has many potential applications to the study of pulmonary toxicology.imagesfigure 1.figure 2 . 
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