A KINETIC MASS-BALANCE MODEL FOR 1,5-ANHYDROGLUCITOL - APPLICATIONS TO MONITORING OF GLYCEMIC CONTROL

The polyol 1,5-anhydroglucitol (AG) present in human plasma is derived largely from ingestion and is excreted unmetabolized. Reduction of pl asma [AG] has been noted in diabetics and is due to accelerated excret ion of AG during hyperglycemia. Plasma [AG] has therefore been propose d as a marker for glycemic control. A precise understanding of its uti lity relies on a quantitative understanding of the mass balance for AG . In this study, non-steady-state data from the literature were analyz ed to develop a dynamic mass balance model for AG that is based on the two-compartment model proposed by Yamanouchi et al. [T. Yamanouchi, Y . Tachibana, H. Akanuma, S. Minoda, T. Shinohara, H. Moromizato, H. Mi yashita, and I. Akaoka. Am. J. Physiol. 263 (Endocrinol. Metab. 26): E 268-E273, 1992]. The data are consistent with a model in which exchang e between tissue and plasma pools is rapid and in which the tissue com partment mass is two to three times the mass of the plasma compartment . According to model estimates, accelerated excretion of AG due to hyp erglycemia can cause marked net depletion of total AG over a time scal e of days. Recovery from a depleted state is slow because the total bo dy capacity represents >5 wk of normal intake. Accordingly, AG monitor ing should be able to indicate the presence of past glucosuric hypergl ycemic episodes during a period of days to weeks, as well as provide i nformation on the extent to which high deviations from the average pla sma glucose concentration are operative.