Developmental gene expression and immunohistochemical study of the human endocrine pancreas during fetal life

The development of human endocrine pancreas has been the subject of many im munohistochemical studies but very little is known at the molecular level. We have determined the patterns of gene expression of glucagon, somatostati n and pancreatic polypeptide during fetal life (16-41 weeks of gestation) u sing the dot-blot hybridization method. In spite of some dispersion in the mRNA levels, no progressive increase or decrease during this period of feta l life could be found, as previously observed for insulin. In keeping with these molecular data, no increase in immunostaining of the four hormones wa s observed, but a dispersion of endocrine cells within the exocrine tissue was noticed at 20 weeks of gestation followed by a clear differentiation of the Langerhans islets at 31 weeks. Interestingly, the mRNA levels of the f our hormones were always higher in the fetal pancreas than in the adult pan creas.