抄録
The effects of 3-hydroxybutyrate (3-OHB) and hyperosmolarity on glucagon secretion were examined in the isolated perfused canine pancreas. When 3-OHB was infused for 15min into the pancreas perfused with 2.8mM glucose, 5 and 20mM sodium 3-OHB inhibited it after a transient stimuration, whereas a similar transient stimulation was observed also by the infusion of 20mM NaCl in a control experiment. The above inhibition was not observed under the perfusate condition of 5.5mM glucose plus 10mM arginine. When the isolated canine pancreas was perfused under the perfusate condition of acidosis (pH 7.1), ketoacidosis (pH 7.1 and 20mM 3-OHB) or hyperosmolarity (+60 mOsm/kg with sucrose) throughout the experiment, the glucagon concentrations produced by 2.8mM glucose under the ketoacidotic and hyperosmolar conditions, were less than half of those obtained under the standard condition. The insulin level was not influenced by the above perfusate conditions. These results suggest that 3-OHB inhibits glucagon secretion stimulated by glucopenia, but does not inhibit it stimulated by amino acids, and that hyperosmolarity inhibits glucagon secretion but does not inhibit insulin secretion. The pathophysiological significance of these results must be slight, considering the presence of hyperglucagonemia during prolonged starvation or diabetic ketoacidosis.
