Synthetic peptide TPLVTLFK (octarphin) reduces the corticosterone production by rat adrenal cortex through nonopioid β-endorphin receptor
Article first published online: 29 JUN 2012
Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.
Journal of Peptide Science
Volume 18, Issue 8, pages 495–499, August 2012
How to Cite
Nekrasova, Y. N., Zolotarev, Y. A. and Navolotskaya, E. V. (2012), Synthetic peptide TPLVTLFK (octarphin) reduces the corticosterone production by rat adrenal cortex through nonopioid β-endorphin receptor. J. Peptide Sci., 18: 495–499. doi: 10.1002/psc.2424
- Issue published online: 18 JUL 2012
- Article first published online: 29 JUN 2012
- Manuscript Accepted: 4 MAY 2012
- Manuscript Revised: 22 APR 2012
- Manuscript Received: 1 MAR 2012
- Russian Foundation for Basic Research. Grant Number: 11-04-00208
- International Science and Technology Center. Grant Number: 2615
- adrenal cortex
The synthetic peptide octarphin (TPLVTLFK) corresponding to the sequence 12–19 of β-endorphin, a selective agonist of nonopioid β-endorphin receptor, was labeled with tritium to a specific activity of 29 Ci/mmol. [3H]Octarphin was found to bind to high-affinity naloxone-insensitive binding sites on membranes isolated from rat adrenal cortex (Kd = 35.7 ± 2.3 nM, Bmax = 41.0 ± 3.6 pmol/mg protein). The binding specificity study revealed that these binding sites were insensitive not only to naloxone but to α-endorphin, γ-endorphin, [Met5]enkephalin, and [Leu5]enkephalin as well. At the same time, the [3H]octarphin-specific binding with adrenal cortex membranes was inhibited by unlabeled β-endorphin (Ki = 32.9 ± 3.8 nM). Octarphin at concentrations of 10−9–10−6 M was found to inhibit the adenylate cyclase activity in adrenocortical membranes, whereas intranasal injection of octarphin at doses of 5 and 20 µg/rat was found to reduce the secretion of corticosterone from the adrenals to the bloodstream. Thus, octarphin decreases the adrenal cortex functional activity through the high affinity binding to nonopioid receptor of β-endorphin. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.