Summary
The effects of dopamine on the release of thyrotropin-releasing hormone (TRH) from
the rat retina in vitro were studied. The rat retina was incubated in the medium 199
(pH 7.4) with 1.0 mg/ml of bacitracin and 100 μg/ml of ascorbic acid. The amount of
TRH release into the medium was measured by radioimmunoassay.
The TRH release from the rat retina was inhibited significantly in a dose-related
manner with the addition of dopamine, but not with pimozide. The inhibitory effects
of dopamine on TRH release from the rat retina were blocked with an addition of pimozide
to the medium. The elution profile of methanol-extracted rat retina on sephadex G-10
was identical to that of synthetic TRH.
From these findings it is concluded that the dopaminergic system inhibits TRH release
from the rat retina in vitro.
Key words
Thyrotropin - Releasing Hormone - Retina - Dopamine - Rat
