Binding of 3H-beta-endorphin to rat brain membranes: characterization of opiate properties and interaction with ACTH.
The binding of tritiated beta-endorphin (3H-beta-EP) to brain homogenates is described. This has been difficult to achieve due to the lack of availability of 3H-beta-EP and to technical difficulties associated with high non-specific binding of beta-EP. We now report that 3H-beta-EP binding is saturable, stereospecific, has high affinity and is inhibited by sodium. Its dissociation rate is ten-fold longer than that of naloxone. Its regional distribution exhibits interesting differences from naloxone and enkephalin binding. ACTH1-24 appears to displace it more effectively than it displaces 3H-naloxone. The results are discussed in terms of multiple transmitter systems and the multiple opiate receptor hypothesis.
D000324:Adrenocorticotropic Hormone / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000378:metabolism*; D004723:Endorphins / Q000378:metabolism*; D066298:In Vitro Techniques; D007700:Kinetics; D008566:Membranes / Q000378:metabolism; D009270:Naloxone / Q000378:metabolism; D051381:Rats; D011957:Receptors, Opioid / Q000378:metabolism; D001615:beta-Endorphin
D004723:Endorphins; D011957:Receptors, Opioid; D009270:Naloxone; D001615:beta-Endorphin; D000324:Adrenocorticotropic Hormone