| Autor: |
OBERHAENSLI, R. D., RAJAGOPALAN, B., TAYLOR, D. J., RADDA, G. K., COLLINS, J. E., LEONARD, J. V. |
| Zdroj: |
Pediatric Research (Ovid); April 1988, Vol. 23 Issue: 4 p375-380, 6p |
| Abstrakt: |
Liver metabolism of two patients (aged 15 and 23 yr) was studied by P-31 magnetic resonance spectroscopy at 1.9 tesla. The P-31 spectra of liver showed the resonances of phosphomonoesters (including sugar phosphates), inorganic phosphate (Pi), phosphodiesters (e.g.glycerophosphorylcholine, glycerophosporylethanolamine), and ATP. These resonances were quantified by expressing their peak areas in mM (assuming that ATP concentrations in normal liver is 2.5 mM) or as a ratio relative to the area of the phosphodiester resonance. After an overnight fast liver phosphomonoesters in patients were 2.6 and 1.6 AU, respectively (controls 1.1 ± 0.5, mean ± 2 SD, n= 17). At the same time liver Pi was decreased in patients to 1.3 and 1.0, respectively (controls 1.8 ± 0.8). Based on chemical shift measurements the increase in phosphomonoesters could be attributed to accumulation of sugar phosphates (mainly glycolytic intermediates). After 1 g/kg oral glucose, hepatic sugar phosphates decreased in patients by 64 and 40, respectively, and reached normal levels (on the absolute intensity scale); whereas liver Piincreased by 130 and 40, respectively. Liver Pilevels remained elevated in both patients 30 min after ingestion of glucose. Liver sugar phosphates and Pidid not change in control subjects (n= 4) after glucose. In contrast to some previous reports, we have found accumulation of glycolytic intermediates in the liver of glucose-6-phosphatase-deficient patients during fasting. In these patients high levels may enhance the activity of residual glucose-6-phosphatase thus increasing hepatic glucose production and reducing the degree of hypoglycemia during fasting. Hyperuricemia is another serious complication of glucose-6-phosphatase deficiency and was present in both patients. Levels of Piare known to regulate synthesis and breakdown purines. The changes in liver Piduring fasting and refeeding in these patients may stimulate production of uric acid and contribute to the hyperuricemia. |
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