POLYAMINES IN PANCREATIC GROWTH

This chapter reviews available data concerning the role of polyamines in pancreatic growth. Like in many other mammalian cells stimulation of pancreatic proliferation by trophic factors is associated with an early increase in ornithine decarboxylase (ODC) activity with consequent putrescine formation. ODC and putrescine play probably an important role in the initiation but not maintenance of pancreatic growth. The application of the specific ODC inhibitor α-difluoromethylornithine (DFMO) alone is not sufficient to judge the role of polyamines in pancreatic growth. For that purpose a combination of substances which inhibit ODC (DFMO) and polyamine oxidase (N1,N4-bisallenylputrescine) and/or S-adenosylmethionine-decarboxylase (SAM-DC) simultaneously has to be investigated. Ideally polyamines from dietary sources and intestinal bacterial flora should be abolished. The uptake of polyamines from the circulation has still to be considered. Studies will be presented proving that though ODC is completely inhibited by DFMO putrescine is still formed via spermidine/spermine N1-acetyltransferase (SAT). The fast increase of ODC in response to growth stimulating factors like cholecystokinin (CCK) is regulated at a pretranslational level by increasing ODC mRNA. © 1990 S. Karger AG, Basel.