title: Effects of calcium hopantenate on the release of thyrotropin-releasing hormone from the rat adrenal gland in vitro.
abstract: The effects of calcium hopantenate (HOPA), a GABA agonist, on the release of thyrotropin-releasing hormone (TRH) from the rat adrenal gland were studied in vitro. The adrenal glands were incubated in medium 199 with 1.0 mg/ml of bacitracin (pH 7.4) (medium) for 20 min. The amount of TRH release into the medium was measured by radioimmunoassay. The TRH release from the rat adrenal gland was inhibited significantly in a dose-related manner with the addition of HOPA to the medium. HOPA's effects on TRH release from the adrenal gland were blocked with the addition of bicuculline, a GABA receptor inhibitor. The elution profile of methanol-extracted rat adrenal gland TRH was identical to that for synthetic TRH. The findings suggest that HOPA inhibits TRH release from the rat adrenal gland, and that its effects are mediated via the GABA receptor.
mesh_terms: D000311:Adrenal Glands / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D002850:Chromatography, Gel; D066298:In Vitro Techniques; D008297:Male; D010205:Pantothenic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D011863:Radioimmunoassay; D051381:Rats; D013973:Thyrotropin-Releasing Hormone / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: C016030:pantogab; D010205:Pantothenic Acid; D005680:gamma-Aminobutyric Acid; D013973:Thyrotropin-Releasing Hormone; D001640:Bicuculline