In vivo immediate early gene expression induced in intestinal and colonic mucosa by feeding.

Since the gut responds rapidly to food intake, the levels of expression of several immediate early genes were measured in mucosa from small and large intestine of rats starved for 3 days or refed. Within 1 h of refeeding, jejunal and ileal c-fos, jun B and zif/268 mRNA and colonic zif/268 dramatically increased. The zif/268 gene in jejunum corresponded in size to the full-length cDNA but, in ileum, an RNA band of about 1.2 kb in size increased greatly after feeding. This represents a physiologic in vivo model for the study of gene regulation associated with intestinal epithelial cellular responses to feeding.