Distribution of β-endorphin-like and adrenocorticotropin-like activities in various tissues of the winter flounder, Pseudopleuronectes americanus

Abstract

1. Different tissues of the winter flounder were extracted with an acidic medium (1 N acetic acid in 0.1 N HCl), 2. ACTH-like activity judged by the ability to stimulate corticosterone production by isolated rat adrenal cells, and opiate receptor binding activity, were present in extracts of the pituitary and brain. 3. Opiate receptor binding activity was absent from the gonadal extract but present in extracts of the heart, liver, interrenal and intestine. 4. β-Endorphin-like immunoreactivity was present in all of the afore-mentioned tissues. 5. Flounder pituitaries were also extracted with Tris-Cl buffer (pH 7.8) and the extract subjected to affinity chromatography on Con A-Sepharose to remove glycoproteins and ultrafiltered to remove high molecular weight materials. 6. When the resulting fraction (mol. wt < 10,000 but >2000) was gel filtered on Sephadex G-10, the unretarded peak contained ACTH-like bioactivity, opiate receptor binding activity and β-endorphin-like immunoreactivity.