Elucidation and characteristics of non-opioid beta-endorphin receptors in rat adrenal cortex

• Published in: Biochemistry (Moscow) 2004-08, Vol.69 (8), p.870-875
• Main Authors: Navolotskaya, E V, Kovalitskaya, Yu A, Zolotarev, Yu A, Kudryashova, N Yu, Goncharenko, E N, Kolobov, A A, Kampe-Nemm, E A, Malkova, N V, Yurovsky, V V, Lipkin, V M
• Format: Article
• Language: English
• Subjects: 11-Hydroxycorticosteroids - blood; 11-Hydroxycorticosteroids - metabolism; 11-Hydroxycorticosteroids - secretion; Adenylyl Cyclases - metabolism; Adrenal cortex; Adrenal Cortex - cytology; Adrenal Cortex - drug effects; Adrenal Cortex - metabolism; Amino Acid Sequence; Animals; beta-Endorphin - pharmacology; Binding Sites; Cell Membrane - drug effects; Cell Membrane - enzymology; Cell Membrane - metabolism; Endorphins; Immunoglobulin Constant Regions; Immunoglobulin gamma-Chains; Male; Naloxone; Oligopeptides - antagonists & inhibitors; Oligopeptides - chemistry; Oligopeptides - metabolism; Oligopeptides - pharmacology; Peptide Fragments - antagonists & inhibitors; Peptide Fragments - chemistry; Peptide Fragments - metabolism; Peptide Fragments - pharmacology; Peptides; Rats; Rats, Wistar; Receptors, Opioid - agonists; Receptors, Opioid - metabolism; Tritium
• ISSN: 0006-2979
• DOI: 10.1023/B:BIRY.0000040218.03078.9f

beta-Endorphin-like decapeptide immunorphin (SLTCLVKGFY), a selective agonist of non-opioid beta-endorphin receptor, was labeled with tritium to specific activity of 24 Ci/mmol. It was used for the detection and characterization of non-opioid beta-endorphin receptors on rat adrenal cortex membranes (Kd1 = 39.6 +/- 2.0 nM, Bmax1 = 40.7 +/- 2.3 pmol/mg protein; Kd2 = 0.25 +/- 0.01 micro M, Bmax2 = 187.8 +/- 9.4 pmol/mg protein). beta-Endorphin was found to inhibit the [3H]immunorphin specific binding to membranes (Ki = 70.0 +/- 9.2 nM); naloxone, [Met5]enkephalin, and alpha- and gamma-endorphins tested in parallel were inactive. Immunorphin at concentrations of 10(-9)-10(-6) M was found to inhibit the adenylate cyclase activity in adrenocortical membranes, while intramuscular injection of immunorphin at doses of 10-100 micro g/kg was found to reduce the secretion of 11-oxycorticosteroids from the adrenals to the bloodstream.