A useful model to study the effect of high sugar concentrations upon growth and enzymic activities of toad embryos and larvae

The aim of this study was to develop an oviparous model suitable for studyi ng the differential effects and mechanisms by which a high concentration of extracellular glucose and other sugars produce diabetes complications, par ticularly body growth retardation during development. Hence, we studied the experimental conditions necessary to obtain measurable effects of high sug ar concentrations (5-mM glucose, mannitol, fructose and galactose) upon bod y growth and development of Bufo arenarum embryos and larvae, and upon the activity of aspartate aminotransferase (AST), gamma-glutamyltransferase (GG T), and alkaline phosphatase (APP). Unfed animals kept in glucose showed lo wer body weight than controls at all stages, a condition only observed at s tage 26 for animals kept in galactose and fructose. All animals reached the same stage of development regardless of the solution in which they were ke pt. Glucose and fructose significantly decreased the activity of all enzyme s tested, while galactose only affected GGT activity. The model provides th e first experimental evidence for the deleterious effect exerted in vivo by different sugars upon developing embryos and larvaes of Bufo arenarum. The results prove that this model might help to elucidate the effects and the pathogenic mechanisms of hyperglycemia upon growth and development of embry os exposed to environments with high sugar concentrations. It might also be come a useful tool for testing the effectiveness of drugs designed to preve nt the deleterious effect of such exposure. (C) 2000 Elsevier science Inc. All rights reserved.