Effects of glucose stimulation on insulin secretion from K and L-cells. Insulin secretion was measured in five K-cell clones (A) and five L-cell clones (B) in response to low (basal, 5 mM) or high (final, 25 mM) glucose. Cell supernatants were collected and insulin was measured by an ELISA. Insulin secretion increased in each of the isolated clones in response to high glucose. Error bars indicate standard deviation.