Secretin is widely expressed during mouse embryonic development

Abstract

The brain-gut peptide secretin has drawn increasing attentions due to its neuroactivities in the brain. In previous prenatal studies, secretin expression was reported after day 17 of gestation in the rat duodenum. Other than this, information on its expression pattern in developing organs and prenatal roles remains unclear. By in situ hybridization and immunohistochemical staining of E10.5, E12.5, E14.5 and E16.5 mouse embryos, secretin transcript and peptide are widely detected during development. They are expressed in several developing brain regions such as cephalic mesenchyme, cerebellar primordium and choroid plexus. Our findings on secretin expression in the cerebellar primordium are consistent with previous reports that both secretin transcript and peptide were detected in the cerebellum in adult rodents. In the developing intestine, however, secretin expression is different from previous report that the peptide is formed in the inner circular muscle rather than in the epithelial villi lining. Other than these organs, secretin is also detected in the developing heart including the ventricular epicardium and myocardium and certain structures of the developing kidney like ureteric bud, collecting duct and glomerulus. Localizations of secretin in distinct cell-types within the developing heart and kidney have provided novel information which RT – PCR and Northern blot analyses were unable to demonstrate in the past. In summary, the wide distribution of secretin in developing embryos strongly suggests for its functional role of in embryonic development.