Lack of glycosilation of pro-opiomelanocortin might account for the periodic acid-Schiff-negative reaction in ACTH cells of teleost fishes.
Unlike tetrapod ACTH cells, teleost ACTH cells do not react with the periodic acid-Schiff method (PAS). To find an explanation for this unique feature, chromatographic fractions obtained after filtration of pituitary extracts of Prochilodus platensis in Sephadex were immunologically analyzed. A high-molecular-weight protein which was identified as pro-opiomelanocortin (POMC) was detected. When this POMC was submitted to affinity chromatography in concanavalin binding, it was not detected. Furthermore, pituitaries incubated in media containing [3H]glucosamine or [3H]fucose did not incorporate these amino acids to the newly synthesized POMC. The results obtained strongly suggest an inability of the fish to glycosilate POMC, and this failure could account for the PAS-negative reaction in the ACTH cells.
D000324:Adrenocorticotropic Hormone / Q000378:metabolism*; D000818:Animals; D050260:Carbohydrate Metabolism; D004723:Endorphins / Q000378:metabolism; D005260:Female; D005399:Fishes / Q000378:metabolism*; D005643:Fucose / Q000378:metabolism; D005944:Glucosamine / Q000378:metabolism; D007163:Immunosorbent Techniques; D008297:Male; D010503:Periodic Acid-Schiff Reaction; D010902:Pituitary Gland / Q000378:metabolism*; D011333:Pro-Opiomelanocortin / Q000378:metabolism*; D011863:Radioimmunoassay; D001615:beta-Endorphin
D004723:Endorphins; D005643:Fucose; D001615:beta-Endorphin; D011333:Pro-Opiomelanocortin; D000324:Adrenocorticotropic Hormone; D005944:Glucosamine