Abstract
Aromatic amino acids and amines which is precursors of adrenaline, were injected subcutaneously in rabbits to study the effect on bloods ugar. L-phenylalanine, L-tyrosine and tyramine had no hyper-glycemic action. The administration of DL-2·4-DOPA caused hyperglycemia, and a more remarkable hyperglycemia occurred following DL-3·4-DOPA and L-3·4-DOPA administration. The administration of dopamine caused a most marked hyperglycemia increasing 2-3 times of the normal level after 3 hours in all experiments. Thus, the hyperglycemic action became more remarkable from the stage of dihydroxyphenyl in the main pathway of adrenaline synthesis.
The effects of various drugs on DOPA and dopamine hyperglycemia were studied. DOPA hyperglycemia was completely inhibited by the intravenous administration of L-α-methyl-DOPA. Dopamine hyperglycemia was not so markedly influenced by the intravenous injection of nialamide (MAOI), and the administration of phentolamine (α-blocker) have slightly inhibited dopamine hyperglycemia, but propranolol (β-blocker) have given no effect. The relationship between dopamine hyperglycemia and adrenergic receptor was not so clear.
DOPA hyperglycemia was not influenced by the intravenous injection of tolbutamide, but was completely inhibited by insulin. Dopamine hyperglycemia was not influenced by the intravenous injection of tolbutamide.
