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Updated: Apr 3, 2026

In Vitro Imaging and Quantification of the Drug Targeting Efficiency of Fluorescently Labeled GnRH Analogues
Published on: March 21, 2017
Characterization of 12 GnRH peptide agonists - a kinetic perspective
Indira Nederpelt1, Victoria Georgi2, Felix Schiele2
1Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research (LACDR), Leiden University, Leiden, The Netherlands.
Background And Purpose:
Drug-target residence time is an important, yet often overlooked, parameter in drug discovery. Multiple studies have proposed an increased residence time to be beneficial for improved drug efficacy and/or longer duration of action. Currently, there are many drugs on the market targeting the gonadotropin-releasing hormone (GnRH) receptor for the treatment of hormone-dependent diseases. Surprisingly, the kinetic receptor-binding parameters of these analogues have not yet been reported. Therefore, this project focused on determining the receptor-binding kinetics of 12 GnRH peptide agonists, including many marketed drugs.
Experimental Approach:
A novel radioligand-binding competition association assay was developed and optimized for the human GnRH receptor with the use of a radiolabelled peptide agonist, [(125) I]-triptorelin. In addition to radioligand-binding studies, a homogeneous time-resolved FRET Tag-lite™ method was developed as an alternative assay for the same purpose.
Key Results:
Two novel competition association assays were successfully developed and applied to determine the kinetic receptor-binding characteristics of 12 high-affinity GnRH peptide agonists. Results obtained from both methods were highly correlated. Interestingly, the binding kinetics of the peptide agonists were more divergent than their affinities with residence times ranging from 5.6 min (goserelin) to 125 min (deslorelin).
Conclusions And Implications:
Our research provides new insights by incorporating kinetic, next to equilibrium, binding parameters in current research and development that can potentially improve future drug discovery targeting the GnRH receptor.
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