Increased urinary excretion of catecholamines and their metabolites in streptozotocin diabetic rat

An attempt has been made to measure changes in the endogenous noradrenaline contents of hearts and brains in rats made diabetic by intravenous administration of streptozotocin. There was no significant change in the endogenous noadrenaline content in the hearts and brains of these diabetic rats. However, all the diabetic animals showed increased excretion of adrenaline, noradrenaline and 3-methoxy-4-hydroxy mandelic acid. This increased excretion was seen as early as 3 days after streptozotocin injections. The rate of disappearance of (3H)-noradrenaline from the heart was significantly higher in these diabetic rats when compared to age-matched controls. It is concluded that there is an increased sympathetic activity in these diabetic animals which is reflected by increased disappearance of (3H)-noradrenaline and increased urinary catecholamine excretion.