Response of the renin-angiotensin-aldosterone system to upright tilting and to intravenous frusemide: effect of prior metoprolol and propranolol.
1 Upright tilting in normal volunteers caused increases in plasma active and total renin, angiotensin II and aldosterone; a slight but significant fall in inactive renin accompanied these changes. 2 The alterations in the renin-angiotensin-aldosterone system on tilting took up to 1 h upright to become fully established. 3 Large intravenous doses of propranolol or metoprolol attenuated, without abolishing, the rises in active renin, angiotensin II, and aldosterone; the attenuation was most evident soon after tilting and was largely overcome by 1 h upright. Inactive renin did not fall significantly after beta-adrenoceptor blockade. 4 Intravenous frusemide caused immediate rises in plasma active, total and inactive renin, angiotensin II, and aldosterone, which then declined over 2 h despite increasing cumulative sodium losses. 5 Intravenous propranolol or metoprolol attenuated, without abolishing, these early increases in the components of the renin-angiotensin-aldosterone system after frusemide. 6 Prior oral metoprolol or propranolol, while significantly slowing the heart, did not limit the early rise in plasma angiotensin II following intravenous frusemide. 7 Thus in contrast to previous workers, we did not find that propranolol eliminated the response of the renin-angiotensin system to upright tilting; in part this difference appeared to be due to the longer tilt we employed. 8 Also in contrast to earlier work, we found attenuation by both intravenous propranolol and metoprolol of the immediate rise in renin after intravenous frusemide.
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000328:Adult; D000804:Angiotensin II / Q000097:blood; D005665:Furosemide / Q000494:pharmacology*; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D008297:Male; D008790:Metoprolol / Q000494:pharmacology*; D011187:Posture; D011412:Propanolamines / Q000494:pharmacology*; D011433:Propranolol / Q000494:pharmacology; D012084:Renin-Angiotensin System / Q000187:drug effects*
D000319:Adrenergic beta-Antagonists; D011412:Propanolamines; D000804:Angiotensin II; D005665:Furosemide; D011433:Propranolol; D008790:Metoprolol