Abstract Insulin-secreting cells (RINm5F) have successfully been grown on a large scale on poly- l-lysine coated-polystyrene microcarriers, providing a high cell number in a restricted volume under conditions that respect the metabolic integrity of these anchorage-dependent cells. The energetic metabolism of the perfused cells hae been followed non-invasively by phosphorus-31 nuclear magnetic resonance spectroscopy. Glucose starvation induced a rapid decrease in nucleoside triphosphates (mainly ATP) pools, correlated with an increase in Pi level. The initial ATP level was rapidly recovered when the cells were refed with glucose or wth mannose, but not with galactose, even after 2 h of perfusion. These differential effects of hexoses on energetic metabolism might be related to their various insulin-release actions on tumor islet cells.