EFFECT OF BIOTIN ON GLUCOKINASE ACTIVITY, MESSENGER-RNA EXPRESSION AND INSULIN RELEASE IN CULTURED BETA-CELLS

Biotin is known to influence hepatic glucokinase (GK) expression both at a transcriptional and at a translational level. The aim of the pres ent paper was to investigate the effect of biotin on pancreatic GK. Fo r this purpose, RIN1046-38 cells were cultured in the presence of diff erent biotin concentrations for different times; thereafter, GK mRNA e xpression, GK activity and insulin release were studied. Results demon strated that biotin has a biphasic effect on GK mRNA expression, being stimulatory after short-term treatment and inhibitory after longterm treatment. GK activity was increased after long-term treatment. Insuli n release was not affected by biotin treat ment. These data suggest th at biotin may influence glucose metabolism also by acting directly at the level of beta-cells.