Effect of [1-Sar,8-Thr]-angiotensin II on the hyperglycemic response to hemorrhage in adrenodemedullated and guanethidine-treated rats.
The present experiments were designed to further investigate the action of an angiotensin II antagonist on the hyperglycemic response to hemorrhage (1.2 ml/100 g b.wt./2 min). The animals were divided into 3 experimental groups; (1) sham-operated animals submitted to intravenous administration of [1-Sar,8-Thr]-angiotensin II (sarthran), an antagonist of angiotensin II (750 ng/100 g b.wt. as a bolus plus an infusion of 25 ng/100 g b.wt./min over 30 min), which greatly attenuated (51.8% lower than controls; P < 0.01) the hyperglycemic response to hemorrhage; (2) animals submitted to adrenodemedullation which decreased the hyperglycemic response to hemorrhage by 64% (P < 0.01). However, sarthran infusion into adrenodemedullated rats caused a 38.5% further decrease in hyperglycemic response to hemorrhage (P < 0.01); and (3) intact animals submitted to blockade of sympathetic noradrenergic pathways by treatment with guanethidine (10 mg/100 g b.wt.), which greatly decreased the baseline value of plasma glucose (64.1 +/- 3.5 mg% vs. 125.3 +/- 4.5 mg%, P < 0.01), and reduced the hyperglycemic response to hemorrhage by 34% (P < 0.01). Sarthran infusion into guanethidine-treated rats caused a further 34% decrease in hyperglycemic response to hemorrhage (P < 0.01). These data indicate that angiotensin II has a direct hyperglycemic effect in addition to its action on sympathetic nervous system activation and adrenomedullary secretion.
Machado
L J
LJ
Department of Physiology and Biophysics, Institute of Biological Science, Federal University of Minas Gerais, Belo Horizonte, Brazil.
Marubayashi
U
U
Reis
A M
AM
Coimbra
C C
CC
D000313:Adrenal Medulla / Q000502:physiology* / Q000601:surgery; D018674:Adrenergic Antagonists / Q000494:pharmacology; D000804:Angiotensin II / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000494:pharmacology; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism*; D006145:Guanethidine / Q000494:pharmacology*; D006470:Hemorrhage / Q000097:blood*; D006943:Hyperglycemia / Q000378:metabolism*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013565:Sympatholytics / Q000494:pharmacology
D018674:Adrenergic Antagonists; D001786:Blood Glucose; D013565:Sympatholytics; D000804:Angiotensin II; C014805:angiotensin II, Sar(1)-Thr(8)-; D006145:Guanethidine