Evidence for the synthesis of multiple pro-opiomelanocortin-like precursors in murine Leydig tumor cells.
The opiate peptide beta-endorphin has recently been localized in extrapituitary tissues and cells, including the Leydig cells of the testis, by immunohistochemical techniques. An intriguing question is whether this localization reflects an accumulation of the peptide through a specific uptake mechanism or is the result of synthesis within the cell in a large precursor form similar to pro-opiomelanocortin synthesized in the pituitary. Evidence is presented herein that specific antibodies against beta-endorphin and adrenocorticotrophic hormone precipitate identical precursor molecules from total cellular mRNA translation products of M5480A Leydig tumor cells. In addition, mRNA from these cells cross-hybridizes under stringent conditions with a cDNA coding for the rat pituitary pro-opiomelanocortin sequence. These data demonstrate the synthesis of a pro-opiomelanocortin-like mRNA in this Leydig cell tumor and strongly implicate biosynthesis within these cells.
D000818:Animals; D001345:Autoradiography; D002460:Cell Line; D011232:Chemical Precipitation; D004723:Endorphins / Q000096:biosynthesis; D007120:Immunochemistry; D007984:Leydig Cell Tumor / Q000378:metabolism; D007985:Leydig Cells / Q000378:metabolism*; D008297:Male; D051379:Mice; D010908:Pituitary Hormones, Anterior / Q000096:biosynthesis* / Q000276:immunology; D011333:Pro-Opiomelanocortin; D014176:Protein Biosynthesis; D011498:Protein Precursors / Q000096:biosynthesis* / Q000276:immunology; D012333:RNA, Messenger / Q000096:biosynthesis; D001615:beta-Endorphin
D004723:Endorphins; D010908:Pituitary Hormones, Anterior; D011498:Protein Precursors; D012333:RNA, Messenger; D001615:beta-Endorphin; D011333:Pro-Opiomelanocortin