title: Neuroblastoma X glioma hybrid cells synthesize enkephalin-like opioid peptides.
abstract: Partially purified extracts from neuroblastoma X glioma hybrid cells 108CC15 inhibit, like opioids, the prostaglandin E1-evoked formation of cyclic AMP in a dose-dependent manner in the same hybrid cells. The inhibition is prevented by the opioid antagonist naloxone. In addition, the same extract competes with [3H]naloxone and [3H]Leu-enkephalin for binding to opioid receptors of hybrid cell membranes and to a specific antiserum, respectively. The opioid activity in the extracts is destroyed by carboxypeptidase A and leucine aminopeptidase, but not by trypsin. Further purification of the extracts by HPLC, TLC, or high-voltage paper electrophoresis reveals in each case two active fractions which behave like Met- and Leu-enkephalin. The Met-enkephalin-like, but not the Leu-enkephalin-like, fraction is inactivated by treatment with BrCN. Dimethylaminonaphtylsulfonyl (dansyl) derivatives of Met- and Leu-enkephalin correspond to [3H]dansyl derivatives of Met-like substances from hybrid cells. Three to four times as much Met-enkephalin-like as Leu-enkephalin-like material is present in the extract. The overall concentration of opioid peptides in the hybrid cells varies between 0.03 and 1.0 pmol Leu-enkephalin equivalents per mg protein. The amount of opioids in the hybrid cells is strongly dependent on the cell density. The findings suggest that neuroblastoma X glioma hybrid cells contain opioid peptides that are very similar, if not identical, to Met- and Leu-enkephalin. Opioid activity can also be detected in other neuronal cell lines and even in glioma cells.
mesh_terms: D000527:Alprostadil; D000818:Animals; D002460:Cell Line; D000242:Cyclic AMP / Q000378:metabolism; D004723:Endorphins / Q000096:biosynthesis*; D004743:Enkephalin, Leucine; D004744:Enkephalin, Methionine; D004745:Enkephalins / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000302:isolation & purification; D005910:Glioma; D006822:Hybrid Cells / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D009270:Naloxone / Q000494:pharmacology; D009447:Neuroblastoma; D010084:Oxidation-Reduction; D011458:Prostaglandins E / Q000494:pharmacology; D051381:Rats
chemical_list: D004723:Endorphins; D004745:Enkephalins; D011458:Prostaglandins E; D009270:Naloxone; D004744:Enkephalin, Methionine; D004743:Enkephalin, Leucine; D000242:Cyclic AMP; D000527:Alprostadil