STUDIES ON EPINEPHRINE AND 3’, 5’-AMP INDUCED HYPERGLYCEMIA EMPLOYING THE ISOLATED PERFUSED RAT LIVER PREPARATION

¹ Department of Pharmacology and Toxicology, The University of Wisconsin Medical School, Madison, Wisconsin

A method for perfusion of the rat liver has been described, with emphasis on the pharmacologic application. A photograph of the apparatus as well as a schematic representation is included. Contrary to previous publications from this and other laboratories, evidence has been presented that rat liver phosphorylase can be activated by exposure to epinephrine, demonstrating that rat liver phosphorylase is not maintained in the activated form at all times. Comparison of infusions of epinephrine and 3’, 5’-AMP showed that both of these agents cause hyperglycemia and phosphorylase activation, but differences were encountered in blood flow studies. Epinephrine caused a marked decrease in blood flow rate whereas the nucleotide did not affect the blood flow rate. Cyclic nucleotide infusions of 0.0002 mg/ml of blood did not elicit hyperglycemia, but at concentrations of 0.002 mg/ml and above definite hyperglycemia was observed. Specificity of the cyclic nucleotide was demonstrated by the absence of hyperglycemia following 5’-AMP infusions at a concentration of 2.4 mg/ml of blood.