Abstract

The polyamines, putrescine, spermidine, and spermine, are believed to play an important role in modulating normal and adaptive intestinal mucosal growth. Polyamine synthesis is rate limited by ornithine decarboxylase (ODC) and ODC activity is specifically inhibited by -difluoromethyl ornithine (DFMO). To assess the importance of polyamines in adaptive growth we first measured mucosal polyamine profiles at different sites in the normal rat intestine and compared the results with those obtained in adaptive hypoplasia (seven days parental nutrition, TPN), in the adaptive hyperplasia of two weeks after 90% small bowel resection (SBR) or pancreatico biliary diversion (PBD). We then examined the effects of DFMO (2% in drinking water, daily from two days before surgery) on the polyamine concentrations and the adaptive response to PBD. The hyperplasia of SBR and PBD was associated with increases in all the polyamine concentrations particularly putrescine. TPN induced a modest degree of hypoplasia and little change in polyamine synthesis resulting in subnormal polyamine concentrations and significantly inhibited the mucosal adaptive response. Changes in polyamine metabolism are important in intestinal mucosal adaptation and by controlling these changes adaptive growth can be controlled.