Dopamine inhibits thyrotropin-releasing hormone release from rat adrenal gland in vitro.
The effects of dopamine on the release of thyrotropin-releasing hormone (TRH) from the rat adrenal gland were studied in vitro. The rat adrenal glands were incubated in medium 199 with 1.0 mg/ml of bacitracin and 100 micrograms/ml of ascorbic acid (pH 7.4) (medium) for 20 min. The amount of TRH release into the medium was measured by radioimmunoassay. The immunoreactive TRH (ir-TRH) release from the rat adrenal gland was inhibited significantly in a dose-related manner with the addition of dopamine and enhanced with the addition of pimozide or domperidone to the medium. Dopamine's effects on ir-TRH release from the adrenal gland were blocked with the addition of pimozide or domperidone. The elution profile of methanol-extracted rat adrenal gland was identical to that of synthetic TRH. The findings suggest that the dopaminergic system inhibits TRH release from the rat adrenal gland.
D000311:Adrenal Glands / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D046508:Culture Techniques; D004294:Domperidone / Q000494:pharmacology; D004298:Dopamine / Q000494:pharmacology*; D008297:Male; D010868:Pimozide / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013973:Thyrotropin-Releasing Hormone / Q000378:metabolism*
D010868:Pimozide; D004294:Domperidone; D013973:Thyrotropin-Releasing Hormone; D004298:Dopamine