Do alterations of endogenous angiotensin II levels regulate erythropoietin production in humans?

What Was Tested

Researchers studied Angiotensin II in this randomized controlled trial publication.

While the administration of exogenous angiotensin II (AII) has been used so far to study its effects, the role of endogenous AII has remained unclear.

Who Took Part

The study group was 12 volunteers.

PubMed indexes the participants as adults, men only.

To alter endogenous AII in humans experimentally the researchers used furosemide bolus injection as a short-term (study 1) and dietary salt as a long-term modulator (study 2).

With the same design, 12 volunteers received high-salt (HS), normal-salt (NS) and low-salt (LS) diet (study 2).

How the Study Was Run

The design is described as randomized, placebo-controlled and crossover.

Random assignment meant chance, not the researchers, decided who got Angiotensin II and who got the comparison, which limits bias.

The comparison arm used a placebo, so changes seen with Angiotensin II could be set against what happens without it.

In the crossover set-up each of the volunteers took both Angiotensin II and the comparison in turn, acting as their own control.

Plasma renin activity (PRA) was analysed along with AII.

Inulin and paraaminohippurate (PAH) clearances were used to indicate glomerular filtration rate (GFR) and renal plasma flow (RPF), respectively.

What Was Measured

PubMed files the paper under topics including Angiotensin II, Diet, Sodium-Restricted, Diuretics, Erythropoietin, Furosemide, Glomerular Filtration Rate and Renin-Angiotensin System.

What This Means in Plain Language

The paper is a randomized, placebo-controlled and crossover study of Angiotensin II in 12 volunteers.

With fewer than 40 people, it is a small study, so it is better read as an early signal for further research than as a settled answer.

The abstract goes on to report its results in about 6 sentences; this page does not restate them, so read the paper for the findings and their limits.

The publication is from 2003 (British journal of clinical pharmacology), a journal based in England.

More context: the Angiotensin II compound page, all human trials.