Effects of acetylcholine on thyrotropin-releasing hormone release from the rat caecum in vitro.
Effects of acetylcholine on the release of thyrotropin-releasing hormone (TRH) from the rat caecum in vitro were studied. The rat caecum was incubated in medium 199 with 1.0 mg/ml of bacitracin and 100 micrograms/ml of ascorbic acid (pH 7.4) (medium). The amount of TRH release into the medium was measured by radioimmunoassay. The immunoreactive TRH (ir-TRH) release from the rat caecum was enhanced significantly in a dose-related manner with the addition of acetylcholine, but not changed with atropine. The stimulatory effect of acetylcholine on ir-TRH release from the rat caecum was blocked with an addition of atropine. Elution profile of acid-methanol-extracted rat caecum on Sephadex G-10 was identical to that of synthetic TRH. The findings suggest that the cholinergic system stimulates TRH release from the rat caecum in vitro.
Mitsuma
T
T
Fourth Department of Internal Medicine, Aichi Medical University, Japan.
Hirooka
Y
Y
Nakata
K
K
Nogimori
T
T
D000109:Acetylcholine / Q000494:pharmacology*; D000818:Animals; D002432:Cecum / Q000187:drug effects / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013973:Thyrotropin-Releasing Hormone / Q000378:metabolism*
D013973:Thyrotropin-Releasing Hormone; D000109:Acetylcholine