Failure of streptozotocin tetraacetate to undergo extensive hydrolysis and to inhibit D-glucose metabolism and insulinotropic action in rat pancreatic islets
✍ Scribed by Elizabeth Olivares; Sally Picton; Luis E. Flores; Marcel M. Kadiata; Willy J. Malaisse
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 96 KB
- Volume
- 16
- Category
- Article
- ISSN
- 0263-6484
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✦ Synopsis
The esteri®cation of several monosaccharides, such as D-glucose, D-mannoheptulose and 2-deoxy-D-glucose was recently reported to increase their biological eciency as either nutrient or antimetabolic agent. In the present study, however, the tetraacetate ester of streptozotocin was unexpectedly found to be less potent than unesteri®ed streptozotocin in inhibiting D-glucose metabolism and insulinotropic action in isolated rat pancreatic islets. This coincided with a much lower rate for the hydrolysis of streptozotocin tetraacetate than D-glucose pentaacetate in islet homogenates. These ®ndings document that the esteri®cation of single sugars is not always a successful procedure to enhance their biological potency, for instance because of too low a rate for the intracellular hydrolysis of the ester. To the extent that the activity of the concerned esterase(s) may dier in distinct cell types, as suggested by a prior observation, advantage could be taken of such a situation to target selected esters towards speci®c, e.g. tumoural cells.