ABSENCE OF CORRELATION BETWEEN PEG AND INSULIN GENE-EXPRESSION IN PANCREAS DURING FETAL DEVELOPMENT

The reg gene characterized in the exocrine pancreas has been found to be expressed in regenerating islets of 90% depancreatized rats and not in normal islets. In humans, it was identified only in the exocrine p ancreas. Because the reg protein has been found to be related to islet cell replication and/or beta cell regeneration, we compared the expre ssion of the reg gene with that of chymotrypsinogen of exocrine origin and insulin of endocrine origin, We investigated the expression of th e three pancreatic genes in the fetal pancreas during human developmen t using dot-blot analysis. The levels of expression of the correspondi ng mRNAs did not appear to undergo great changes between the 17th and the 29th wk of gestation, Nevertheless, the fetal mRNA levels for reg and chymotrypsinogen were below that of the adult, with very low level s of reg gene expression in more than half of the studied pancreases, In contrast, the insulin mRNA levels were significantly higher in feta l than in adult pancreases, suggesting that insulin may function as a growth factor during fetal development, Our results indicate that no c orrelation be tween reg and insulin gene expression exists in the feta l pancreas during the developmental period studied but, on the contrar y, such a correlation was present in the adult pancreas.