title: Met- and leu-enkephalin immuno- and bio-reactivity in human stomach and pancreas.
abstract: Acid extracts of human pancreas and gastric corpus and antral mucosa and muscularis were investigated for the presence of met-enkephalin and leu-enkephalin by radioimmunoassay, Sephadex chromatography and radioreceptor assay. As the assays for leu-enkephalin crossreacted with those for met-enkephalin, only cyanogen bromide-treated samples were used for the determination of leu enkephalin. Met-enkephalin immunoreactivity was destroyed by more than 94% when treated with cyanogen bromide. Serial extract dilutions displaced 125 I labelled met-enkephalin and 125 I leu-enkephalin in the respective enkephalin radioimmunoassay both roughly parallel to the standard curves. Sephadex chromatography of the extracts resulted in elution of met-enkephalin and leu-enkephalin immunoreactivity similar to the size of 3H-met-enkephalin, and these eluates displaced 3H-met-enkephalin from rat brain membranes in an opioid radioreceptor assay. The highest concentration of met-enkephalin and leu-enkephalin immunoreactivity in tissue obtained at surgery was in the mucosa of the body of the stomach. Met- and leu-enkephalin receptor bioreactivity concentrations exceeded immunoreactivity concentrations. These investigations provide evidence of the presence of met-enkephalin- and leu-enkephalin-like substances in human stomach and pancreas.
mesh_terms: D002850:Chromatography, Gel; D003429:Cross Reactions; D003488:Cyanogen Bromide; D004743:Enkephalin, Leucine / Q000032:analysis*; D004744:Enkephalin, Methionine / Q000032:analysis*; D006801:Humans; D010179:Pancreas / Q000032:analysis*; D011863:Radioimmunoassay; D011869:Radioligand Assay; D013270:Stomach / Q000032:analysis*; D014020:Tissue Extracts / Q000032:analysis*
chemical_list: D014020:Tissue Extracts; D004744:Enkephalin, Methionine; D004743:Enkephalin, Leucine; D003488:Cyanogen Bromide