THYROTROPIN-RELEASING-HORMONE AND SOMATOSTATIN INHIBIT EACH OTHERS RELEASE IN-VITRO IN THE RAT RETINA

The effect of thyrotropin-releasing hormone (TRH), somatostatin (SS) o r octreotide, an analogue of SS, on release of TRH or SS from the rat retina was studied in vitro. The retina was incubated in medium 199 (p H 7.4) with 1.0 mg/ml of bacitracin (medium) for 20 min. The amount of TRH or SS release into the medium was measured by individual radioimm unoassays. The TRH release from the rat retina was inhibited significa ntly in a dose-related manner by the addition of SS or octreotide. The SS release from the retina was inhibited by TRH, and the inhibitory e ffect of TRH on SS release from the rat retina was blocked by the addi tion of anti-TRH receptor antiserum immunoglobulin fraction. The findi ngs suggest an interaction between TRH and SS in the rat retina by whi ch the addition of one inhibits the release of the other.