The use of 13C-labelled glycosyl ureides for evaluation of orocaecal transit time.

In the present study, cellobiose-[13C]ureide and glucose-[13C]ureide were synthesized and tested as alternative substrates for noninvasive evaluation of the orocaecal transit time (OCTT). Experimental study. In total, 1 g cellobiose-[13C]ureide was administered together with a continental breakfast either without or after predosing of 5 x 1 g unlabelled cellobiose ureide on the day prior to study commencement. After 2 weeks, the same subjects ingested glucose-[13C]ureide (dosage: 0.57 g) either without or after predosing of the respective unlabelled ureide under identical conditions. Expired air samples were taken over 10 h. 13CO2-enrichment was measured by isotope ratio mass spectrometry (PDZ Europa, Sandbach, UK). The OCTT was calculated from the interval between 13C-ureide administration and the detection of a significant and sustained 13C-rise of 2 delta over baseline in breath. University of Rostock, Children's Hospital, Research Laboratory. Eight healthy adults aged 22-55 y. After application of cellobiose-[13C]ureide and glucose-[13C]ureide OCTTs of 401 and 415 min, respectively, were measured. The predosing resulted in higher and steeper 13C-enrichments and caused a significant shortening of OCTTs of 265 and 287 min, respectively (P=0.012 and 0.017). The onset of 13CO2-enrichment reflected the degradation of glycosyl-[13C]ureides by glucose ureide hydrolase. The predosing with unlabelled ureides prior to pulse labelling with cellobiose-[13C]ureide and glucose-[13C]ureide (the latter is the key substance of the enzymatic sugar-ureide degradation) led to an induction of enzyme activity and resulted in a more precise and similar estimation of the OCTT when using both 13C-labelled ureides.

Citation

K D Wutzke, B Glasenapp. The use of 13C-labelled glycosyl ureides for evaluation of orocaecal transit time. European journal of clinical nutrition. 2004 Apr;58(4):568-72

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PMID: 15042123

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