Endothelin-1 infusion inhibits plasma insulin responsiveness in normal men

What Was Tested

Researchers studied Endothelin-1 in this randomized controlled trial publication.

Elevated plasma endothelin (ET)-1 levels have been described in insulin-resistant states such as syndrome X, obesity, non-insulin-dependent diabetes mellitus, and in some studies in essential hypertension.

Who Took Part

According to the abstract, 10 subjects were involved.

PubMed indexes the participants as adults, men only.

Using dynamic assessment by the minimal model approach with the modified frequent sampling intravenous glucose tolerance test (FSIGT) the following and other parameters were measured: insulin sensitivity; acute insulin response to glucose (AIR(G)) calculated as the average of the three peak values between 2 and 5 min after injection of glucose from which the basal insulin levels were subtracted; the initial area under the curve (AUC(1-19)) from insulin values between time 0 and 19 min and the first-phase insulin secretion (phi1) from insulin kinetics parameters.

How the Study Was Run

The researchers set it up as a randomized, single-blind, placebo-controlled and crossover study.

Random assignment meant chance, not the researchers, decided who got Endothelin-1 and who got the comparison, which limits bias.

In this single-blind Endothelin-1 study one party knew the assignments and the other did not.

Some subjects received a placebo instead of Endothelin-1, giving a reference point.

In the crossover set-up each of the subjects took both Endothelin-1 and the comparison in turn, acting as their own control.

What Was Measured

The subject headings attached to it are Endothelin-1, Insulin, Insulin Antagonists and Insulin Resistance.

What This Means in Plain Language

The paper is a randomized, single-blind and placebo-controlled study of Endothelin-1 in 10 subjects.

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.

Its findings take up roughly 3 sentences of the abstract and are left out here on purpose; the source paper is the place to read them.

The publication is from 1998 (Journal of hypertension), a journal based in Netherlands.

More context: the Endothelin-1 compound page, all human trials.