The length of the silent lag-time before elevation of the cytosolic free Ca²⁺ ([Ca²⁺]_i) differs between individual pancreatic ß-cells. One important question is whether these differences reflect a random phenomenon or whether the length of lag-time is inherent to the individual ß-cell. We compared the lag-times, initial dips and initial peak heights for ([Ca²⁺]_i from two consecutive glucose stimulations (with either 10 or 20 mM glucose) in individual ob/ob-mouse ß-cells, using the fura-2 technique in a microfluorimetric system. There was a strong correlation between the lengths of the lag-times in each ß-cell (r = 0.94, P<0.001 (10 mM glucose) and r = 0.96, P<0.001 (20 mM glucose)) as well as between the initial dips in ([Ca²⁺]_i (10 mM glucose r = 0.93, P<0.001 and for 20 mM glucose, r = 0.79, P<0.001) and between the initial peak heights (10 mM glucose, r = 0.51, P< 0.01 and for 20 mM glucose, r = 0.77, P<0.001). These data provide evidence that the response pattern, including both the length of the lag-time and the dynamics of the subsequent [Ca²⁺]_i, is specific for the individual ß-cell.