Pancreatic exocrine secretions as a source of luminal polyamines in pigs

The goal of the present study was twofold: (1) to detect the possible stora ge of dietary polyamines (PAs) in various tissues and (2) to investigate th e role of dietary PAs in the differentiation of the pig intestinal epitheli um. A first experimental series was designed to assess the accumulation of either milk PAs (mostly spermidine) or orally administered spermine (SPM) i n piglet red blood cells (RBCs) and plasma, a preliminary stage in their di stribution to growing and storage organs. Though PA concentrations of pigle t RBCs and plasma were generally significantly higher than their sow counte rparts, our experimental conditions failed to demonstrate that this increas e could stem from ingested PAs. A second experimental series dealt with the determination of disaccharidase specific activities in proximal and distal parts of piglet gut on the 26th and 29th days after birth (preweaning time ). In agreement with observations made previously on rat pups, we observed an increase in maltase specific activity (SA) at the end of the suckling pe riod (the observed increase in sucrase SA was not significant). However, or ally administered SPM did not affect this activity. Compared to the constan t protein concentrations observed in both parts of the gut, the pancreatic protein content decreased sharply between the 26th and 29th postnatal days. At the same time pancreatic concentrations of spermidine (SPD) also decrea sed, suggesting that some pancreatic PAs were released as the organ secrete d its proteins. In accordance with this hypothesis, we recorded SPM and SPD in pancreatic juice. The increases in PA concentrations seemed to follow t he protein secretion pattern (i.e. PA concentrations reached a maximal valu e when the protein concentration was highest). The presence of PAs in pancr eatic juice could be indicative of a control mechanism exerted by the pancr eas on PA-induced growth and differentiation of porcine intestinal epitheli um.