Progastrin expression in mammalian pancreas.

AUTOR(ES)

Bardram, L

RESUMO

Expression and processing of progastrin were examined in fetal, neonatal, and adult pancreatic tissue from five mammalian species (cat, dog, man, pig, and rat). A library of sensitive, sequence-specific immunoassays for progastrin and its products was used to monitor extractions and chromatography before and after cleavage with processing-like enzymes. The results showed that progastrin and its products are expressed in the pancreas of all species in total concentrations varying from 0.3 to 58.9 pmol/g of tissue (medians). The degree of processing was age- and species-dependent. In comparison with adult pancreatic tissue the fetal or neonatal pancreas processed a higher fraction to bioactive, C-terminally amidated gastrin. Nevertheless, the pancreatic processing was always less complete than that of the adult antral mucosa. The moderate level of expression and the attenuated processing in the adult pancreas contribute to explain previous failures to detect gastrin in normal pancreatic tissue. Our results indicate that gastrin-producing tumors in the pancreas are not ectopic, but arise from cells that normally express the gastrin gene.

Documentos Relacionados

• Expression of peptide receptors in human endocrine tumours of the pancreas.
• Onset of cell-specific gene expression in the developing mouse pancreas.
• Enhanced insulin-like growth factor I gene expression in regenerating rat pancreas.
• Opioid polypeptides in guinea pig pancreas.
• Distinct cholecystokinin receptors in brain and pancreas.