Effect of bacitracin on the degradation of a vasopressin receptor ligand with high affinity for the V1 and V2 vasopressin isoreceptors.
We previously described a new iodinated vasopressin analogue (N epsilon-[125I]L-Tyr-[Lys8]-vasopressin) with high affinity for the vasopressin V1 and V2 isoreceptors. The aim of the present study was: i) to analyse the degradation pathway of N epsilon-[125I]L-Tyr-[Lys8]-vasopressin and (ii) to look for an effective inhibitor of radioligand degradation. N epsilon-[125I]L-Tyr-[Lys8]-vasopressin was processed in a temperature-dependent manner by crude cell membranes from LLC-PK1 cells. Only one degradation product was seen using RP-HPLC. The degradation product co-eluted with monoiodotyrosine. The stereoisomer, N epsilon-[125I]D-Tyr-[Lys8]-vasopressin, underwent the same degradation process. Bacitracin prevented degradation at doses as low as 40 mg/l without alterating the binding affinity.
Hocher
B
B
Abteilung für Innere Medizin, Klinikum Steglitz, Freie Universität Berlin, Germany.
Dürr
J A
JA
Hensen
J
J
D000818:Animals; D065092:Antidiuretic Hormone Receptor Antagonists; D001414:Bacitracin / Q000494:pharmacology*; D002460:Cell Line; D002462:Cell Membrane; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D007684:Kidney Tubules / Q000187:drug effects*; D008024:Ligands; D008236:Lypressin / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000378:metabolism; D017483:Receptors, Vasopressin / Q000378:metabolism*; D013552:Swine; D014667:Vasopressins / Q000037:antagonists & inhibitors / Q000378:metabolism*
D065092:Antidiuretic Hormone Receptor Antagonists; D008024:Ligands; D017483:Receptors, Vasopressin; C087880:vasopressin, N(epsilon)-tyrosyl-8-lysyl-; D014667:Vasopressins; D001414:Bacitracin; D008236:Lypressin