Fig. 8.
In control islets, reducing glucose from 7 to 1 mM decreases somatostatin and insulin secretion (solid curved line; B and C) and increases glucagon secretion (solid curved line; A), as shown by the intraislet hormone concentrations. In the absence of insulin, corresponding to severe diabetes, somatostatin is below control in G7 and above control in G1 (dashed line; B). In this case, the basal level of somatostatin was increased (bas = 0.0015). Glucagon secretion is above control in G7 and below control in G1 (dashed line; A). Blocking somatostatin receptors increases glucagon secretion, especially in G1 (dotted and dashed line; A). Relation of KATP conductance to the bell-shaped curve is the same as in Fig. 5.