Effect of sympathoadrenal blockade on the hyperglycemic action of angiotensin II

The present experiments were designed to investigate the influence of the sympathoadrenal system on the hyperglycemic action of angiotensin II in freely moving rats divided into four experimental groups: (1) sham-operated animals submitted to intravenous administration of angiotensin II (1.9 nmol) which caused a rapid increase in plasma glucose reaching the highest values at 5 min after the injection (26.5% of the initial values; P < 0.01); (2) Sham-operated animals submitted to blockade of sympathetic noradrenergic pathways by treatment with guanethidine (10 mg/100 g body weight), which greatly decreased the baseline value of plasma glucose (85 +/- 5.5 mg% vs 136 +/- 5.1 mg% P < 0.01), and increased the hyperglycemic response to angiotensin II by 96% (P < 0.01); (3) Animals submitted to adrenodemedullation that did not alter the hyperglycemic response to angiotensin II; (4) Adrenodemedullated animals submitted to sympathetic blockade by guanethidine treatment which caused a 40.5% decrease in the hyperglycemic response to angiotensin II (P < 0.05). These data indicate that angiotensin II has a direct hyperglycemic effect in addition to its action on sympathetic nervous system activation and adrenomedullary secretion.