Background-Polyamines are essential for cell growth. Dietary and probably gut bacterial derived polyamines contribute significantly to the polyamine body pool. Aims-To evaluate the influence of dietary, luminal polyamines on growth and development of diVerent gastrointestinal organs in normally growing rats. Methods-Male suckling Wistar rats were randomly allocated to four treatment groups: polyamine deficient diet (PDD); PDD plus antibiotics (neomycin 2 g/kg and metronidazole 34 mg/kg); PDD plus polyamine supplementation at normal concentrations; or normal standard laboratory chow. After a six month feeding period 7-10 animals/group were sacrificed. Results-No diVerences in body weight gain, food consumption, or general behaviour could be observed between the four groups of animals. Feeding of PDD alone or PDD plus antibiotics resulted in a highly significant decrease in organ weight, protein content, and DNA content in small intestinal and colonic mucosa whereas no alterations were found in the liver. Conclusions-Long term feeding of polyamine deficient diets resulted in a significant hypoplasia of small intestinal and colonic mucosa. Dietary, luminal polyamines are important local factors for growth and the development of small intestinal and colonic mucosa. (Gut 1999;44:12-16)

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Tracer doses of Mg28 were used to study the metabolism of parenterally administered magnesium. Plasma clearance was rapid, and accumulation of radioactivity in bone started within 2 hours. Of the tissues studied, skin and muscle showed the lowest concentrations of Mg28. In most tissues the ratio of tissue to serum radioactivity became fairly constant after 18 hours. The values for the exchangeable body pool of magnesium, calculated from the specific activities of urine specimens obtained between 18 and 24 hours, approximated the carcass content of magnesium. During starvation the renal excretion of endogenous magnesium amounted to 61.7 mEq/kg of weight loss.

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