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DOPAMINE IS A PHYSIOLOGICAL REGULATOR OF THYROTROPHIN (TSH) SECRETION IN NORMAL MAN
Author(s) -
SCANLON M. F.,
WEIGHTMAN D. R.,
SHALE D. J.,
MORA B.,
HEATH M.,
SNOW M. H.,
LEWIS M.,
HALL R.
Publication year - 1979
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/j.1365-2265.1979.tb03028.x
Subject(s) - metoclopramide , endocrinology , medicine , dopamine , radioimmunoassay , basal (medicine) , euthyroid , circadian rhythm , dopamine antagonist , hormone , haloperidol , insulin , vomiting
SUMMARY Using a sensitive and precise radioimmunoassay for human TSH we have demonstrated significant elevations in serum TSH levels in euthyroid volunteers following administration of the dopamine receptor blocking drug metoclopramide when compared with placebo. The degree of TSH response is significantly greater in females than in males and is sustained over a 3‐hour period after a single oral 10 mg dose of metoclopramide. The degree of TSH release after metoclopramide is inversely related to the basal TSH level suggesting that dopamine is a determinant of low daytime TSH levels and is thus implicated in the circadian rhythm of TSH secretion. Pretreatment with 10 mg of metoclopramide orally, one hour before TRH administration leads to significant enhancement of the TSH response to TRH. Our findings provide further evidence for the physiological inhibitory role of dopamine in the control of TSH secretion in normal man. The possible mode of action of dopamine and the clinical implications of this neuroregulatory pathway are discussed.