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A 31P NMR study of the GI tract: Effect of fructose loading and measurement of transverse relaxation times

✍ Scribed by G. S. Karczmar; N. J. Tavares; M. W. Weiner

Publisher
John Wiley and Sons
Year
1989
Tongue
English
Weight
412 KB
Volume
9
Category
Article
ISSN
0740-3194

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✦ Synopsis

The effect of fructose loading on high-energy phosphates in the jejunum, ileum, and large intestine ofrats was studied using "P NMR. Following fructose loading, an increase in the intensity of the PME resonance was observed in the jejunum, indicating an accumulation of fructose-I-phosphate. There were no significant changes in ATP or Pi. This demonstrates that the activity of fructokinase in the jejunum can be monitored by ''P NMR. Fructose loading had no detectable effect on metabolite levels in the ileum and large intestine. Resolution of intestinal spectra was poor due to unusually large linewidths and the presence of broad underlying signals. To study the mechanism of line broadening, the T2's of the phosphorus resonances were measured using a solenoidal coil. The T2's ofthe ATP, Pi, PME. and PCr resonances were much longer than the T:'s, suggesting that the linewidths of these resonances are primarily due to susceptibility gradients and/or compartmentation of metabolites. Other signals, particularly in the PDE region, were homogeneously broadened and had very short T2's. Spin echoes obtained with evolution times of 1 to 4 ms suppressed these broad components, with little loss of intensity in the inhomogeneously broadened resonances; as a result, resolution was improved.

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