Lack of evidence for pituitary thyrotroph down-regulation after 1 week of oral thyrotrophin-releasing hormone and metoclopramide under conditions of constant peripheral thyroid hormone levels.

What Was Tested

This randomized controlled trial looks at Metoclopramide and Thyroxine.

The researchers investigated the pituitary thyrotrophin (TSH) response to repeated oral (non-pulsatile) thyrotrophin-releasing hormone (TRH) administration and potential modifying effects of dopamine antagonist treatment under conditions of constant peripheral thyroid hormone levels.

Who Took Part

The age groups tagged for this paper are adults and middle-aged adults, both men and women.

At the beginning and end of each treatment period five samples of blood for estimation of serum TSH were taken over 1 h before ("baseline") and seven samples over 2 h after the treatment combination was given ("stimulated").

How the Study Was Run

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

The participants were allocated by chance, so the Metoclopramide group and the comparison group should start out alike.

Blinding on both sides kept the participants and researchers unaware of who received Metoclopramide.

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

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

Serum free thyroxine, free triiodothyronine and prolactin levels also were measured.

What Was Measured

The researchers investigated the pituitary thyrotrophin (TSH) response to repeated oral (non-pulsatile) thyrotrophin-releasing hormone (TRH) administration and potential modifying effects of dopamine antagonist treatment under conditions of constant peripheral thyroid hormone levels.

Topics PubMed links to this paper include Down-Regulation, Metoclopramide, Pituitary Gland, Anterior, Thyroid Hormones, Thyrotropin, Thyrotropin-Releasing Hormone and Thyroxine.

What This Means in Plain Language

The paper is a randomized, double-blind and placebo-controlled study of Metoclopramide and Thyroxine.

The publication is from 1995 (European journal of endocrinology), a journal based in England.

More context: all human trials.