The effects of low dose insulin infusions on the renin angiotensin and sympathetic nervous systems in normal man.
To examine the effects of physiological insulin concentrations on the renin-angiotensin and sympathetic nervous systems, healthy volunteers were studied by the euglycaemic glucose clamp technique with sequential 60 min 0.5 and 1.0 mU kg-1 min-1 insulin infusions and, subsequently, by a control infusion simulating clamp conditions. Plasma renin activity increased from 0.8 +/- 0.1 ng ml-1 h-1 basally to 1.0 +/- 0.2 ng ml-1 h-1 during the 0.5 mU infusion to 1.4 +/- 0.1 ng ml-1 h-1 during the 1 mU infusion but did not change during control infusion (0.9 +/- 0.3 ng ml-1h-1 to 0.9 +/- 0.2 ng ml-1h-1 to 1.0 +/- 0.1 ng ml-1h-1) (P less than 0.001 insulin vs. control by ANOVAR). Plasma angiotensin II increased during insulin (21.2 +/- 1.8 to 25.2 +/- 2.3 to 29.3 +/- 2.4 pg ml-1) but not during control infusion (24.0 +/- 2.8 to 23.6 +/- 2.6 to 23.5 +/- 2.5 pg ml-1) (P less than 0.001 insulin vs. control). Serum aldosterone did not change significantly during either infusion (insulin: 239 +/- 89 pmol l-1 to 237 +/- 50 pmol l-1 to 231 +/- 97 pmol l-1, control: 222 +/- 79 to 237 +/- 50 to 213 +/- 97 pmol l-1). Plasma noradrenaline increased to a greater extent during insulin (1.03 +/- 0.2 to 1.14 +/- 0.8 to 1.27 +/- 0.17 nmol l-1) than control infusion (0.86 +/- 0.09 to 0.97 +/- 0.09 to 0.99 +/- 0.09 nmol 1-1 (P less than 0.01 insulin vs. control). Changes in mean systolic blood pressure during insulin infusion were significantly different from control (+ 3 vs. -4 mmHg, P less than 0.001). In conclusion acute hyperinsulinaemia within the physiological range increases circulating hormones of the renin-angiotensin and sympathetic nervous systems and also increases systolic blood pressure.
Sir George E. Clark Metabolic Unit, Royal Victoria Hospital, Belfast, UK.
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Rooney
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Edgar
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Sheridan
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Atkinson
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Bell
D000328:Adult; D000450:Aldosterone / Q000097:blood; D000804:Angiotensin II / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism; D001794:Blood Pressure / Q000187:drug effects; D004837:Epinephrine / Q000097:blood; D006801:Humans; D007262:Infusions, Intravenous; D007328:Insulin / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D008297:Male; D009638:Norepinephrine / Q000097:blood; D011188:Potassium / Q000097:blood; D012083:Renin / Q000097:blood; D012084:Renin-Angiotensin System / Q000187:drug effects* / Q000502:physiology; D013564:Sympathetic Nervous System / Q000187:drug effects* / Q000502:physiology
D001786:Blood Glucose; D007328:Insulin; D000804:Angiotensin II; D000450:Aldosterone; D012083:Renin; D011188:Potassium; D009638:Norepinephrine; D004837:Epinephrine