Abstract
It is commonly believed that lactulose lowers the blood NH4 by acidification of the colonic contents and by its laxative effects. We have reason to believe that the major effect of lactulose on blood NH4 is due to bacterial absorption of NH4. To differentiate between the effects of pH and the presence of an energy source, 4 suspensions were prepared from single stool specimens of 19 healthy volunteers. 2 suspensions were kept at pH 7.0 and two at pH 5.0. After 6 and 18 h of incubation lactulose (62mg/g) was added to 1 suspension of each pH. NH4 was measured after 1, 6, 12, 18 and 24h.
Mean NH4 conc. in Contr pH5 compared to Contr pH7 was 56.4% after 24h. Addition of lactulose invariably caused a large decrease in NH4, resulting in mean conc. of 4.4% (pH7) and 7.9% (pH5) compared to control incubations. We conclude that lactulose reduces already formed NH4. This is pH independent. The NH4 reduction is caused by bacterial utilization and exerts a more important effect on lowering NH4 than the slower production rate caused by acidification.
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van der Burg, G., Douwes, A., Ides, E. et al. 34 LACTULOSE AND AMMONIA METABOLISM. Pediatr Res 24, 410 (1988). https://doi.org/10.1203/00006450-198809000-00057
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DOI: https://doi.org/10.1203/00006450-198809000-00057