Impaired dopaminergic control of thyroid stimulating hormone secretion in chronic renal failure.

After administration of intravenous metoclopramide, a dopaminergic receptor blocking agent, no rise in thyroid stimulating hormone (TSH) could be found in patients with chronic renal failure, in contrast to non-uraemic controls. Basal TSH values were normal in the uraemic patients but the TSH response to thyrotrophin-releasing hormone (TRH) was significantly reduced. These results suggest that a discrete abnormality in the hypothalamo-pituitary axis exists in uraemia which may in part be due to interference with central dopaminergic control by a uraemic toxin.