INHIBITORY EFFECT OF THYROTROPIN-RELEASING-HORMONE ON ENZYME-SECRETION FROM ISOLATED RAT PANCREATIC ACINAR-CELLS

This study reports a direct effect of TRH on amylase secretion from is olated rat exocrine pancreatic acinar cells, TRH inhibited carbachol ( 10(-5) M)-stimulated amylase secretion by a maximum of 24% at a concen tration of 10(-11) M (p < 0.05), but did not affect basal amylase rele ase in concentrations from 10(-13) M to 10(-8) M, Ceruletide (3 x 10(- 10) M)-stimulated amylase secretion was maximally reduced by 23% at a TRH concentration of 10(-10) M (p < 0.05). Direct stimulation of prote inkinase C-mediated secretion by the diacylglycerol analogue 1-oleoyl- 2-acetyl-sn-glycerol (OAG) was not altered by TRH. The TRH metabolite cycle (His-Pro) did not influence basal or stimulated pancreatic secre tion in vitro, These findings point to a TRH-mediated modulation of ex ocrine pancreatic secretion at the receptor site.