Enzymatic response to glucocorticoids of the chick intestinal endoderm associated with various mesenchymal cell types

The aim of the present study was to test the morphological and functional maturation of recombinants composed of chick intestinal endoderms associated to different mesenchymal supports and their enzymatic response to glucocorticoids. For this purpose 5.5-day chick embryonic intestinal endoderm has been associated to 14-day fetal rat gut mesenchyme, to rat intestinal fibroblasts (6-day neonatal rat intramucosal fibroblasts) or to rat control fibroblasts, originating from 20-day fetal rat skin and lung and from 6-day neonatal rat intestinal muscle. The recombinants were grown as intracoelomic grafts either for 12 days or for 10 days plus 2 days in organ culture in the presence of dexamethasone. The data show that heterospecific recombinants achieve subnormal morphogenesis and enzymatic maturation. The organ culture experiments further reveal that sucrase activity is insensitive to dexamethasone in all types of recombinants whereas, alkaline phosphatase is highly stimulated over the levels present in the intestine developed in situ whatever the stromal support, except when this support is provided by rat gut mesenchyme. These results support the view that in the intestine the hormonal response is mediated by epithelial-mesenchymal interactions.