Antagonistic actions of analogs related to growth hormone-releasing hormone (GHRH) on receptors for GHRH and vasoactive intestinal peptide on rat pituitary and pineal cells in vitro

Z. Rékási, Jozsef L. Varga, Andrew V. Schally, Gabor Halmos, Kate Groot, T. Czömpöly

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Abstract

Peptide analogs of growth hormone-releasing hormone (GHRH) can potentially interact with vasoactive intestinal peptide (VIP) receptors (VPAC1-R and VPAC2-R) because of the structural similarities of these two hormones and their receptors. We synthesized four new analogs related to GHRH (JV-1-50, JV-1-51, JV-1-52, and JV-1-53) with decreased GHRH antagonistic activity and increased VIP antagonistic potency. To characterize various peptide analogs for their antagonistic activity on receptors for GHRH and VIP, we developed assay systems based on superfusion of rat pituitary and pineal cells. Receptor-binding affinities of peptides to the membranes of these cells were also evaluated by radioligand competition assays. Previously reported GHRH antagonists JV-1-36, JV-1-38, and JV-1-42 proved to be selective for GHRH receptors, because they did not influence VIP-stimulated VPAC2 receptor-dependent prolactin release from pituitary cells or VPAC1 receptor-dependent cAMP efflux from pinealocytes but strongly inhibited GHRH- stimulated growth hormone (GH) release. Analogs JV-1-50, JV-1-51, and JV-1-52 showed various degrees of VPAC1-R and VPAC2-R antagonistic potency, although also preserving a substantial GHRH antagonistic effect. Analog JV-1- 53 proved to be a highly potent VPAC1 and VPAC2 receptor antagonist, devoid of inhibitory effects on GHRH-evoked GH release. The antagonistic activity of these peptide analogs on processes mediated by receptors for GHRH and VIP was consistent with the binding affinity. The analogs with antagonistic effects on different types of receptors expressed on tumor cells could be utilized for the development of new approaches to treatment of various human cancers.

Original languageEnglish
Pages (from-to)1218-1223
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume97
Issue number3
DOIs
Publication statusPublished - Feb 1 2000

Fingerprint

Growth Hormone-Releasing Hormone
Vasoactive Intestinal Peptide
Receptors, Vasoactive Intestinal Peptide, Type II
Receptors, Vasoactive Intestinal Polypeptide, Type I
Peptides
Growth Hormone
Vasoactive Intestinal Peptide Receptors
Lactotrophs
Hormone Antagonists
Radioligand Assay
In Vitro Techniques
somatotropin releasing hormone receptor
Neoplasms
Cell Membrane
Hormones

Keywords

  • Cancer therapy
  • Growth hormone-releasing hormone and vasoactive intestinal peptide antagonists
  • Structure-activity relationships

ASJC Scopus subject areas

  • Genetics
  • General

Cite this

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title = "Antagonistic actions of analogs related to growth hormone-releasing hormone (GHRH) on receptors for GHRH and vasoactive intestinal peptide on rat pituitary and pineal cells in vitro",
abstract = "Peptide analogs of growth hormone-releasing hormone (GHRH) can potentially interact with vasoactive intestinal peptide (VIP) receptors (VPAC1-R and VPAC2-R) because of the structural similarities of these two hormones and their receptors. We synthesized four new analogs related to GHRH (JV-1-50, JV-1-51, JV-1-52, and JV-1-53) with decreased GHRH antagonistic activity and increased VIP antagonistic potency. To characterize various peptide analogs for their antagonistic activity on receptors for GHRH and VIP, we developed assay systems based on superfusion of rat pituitary and pineal cells. Receptor-binding affinities of peptides to the membranes of these cells were also evaluated by radioligand competition assays. Previously reported GHRH antagonists JV-1-36, JV-1-38, and JV-1-42 proved to be selective for GHRH receptors, because they did not influence VIP-stimulated VPAC2 receptor-dependent prolactin release from pituitary cells or VPAC1 receptor-dependent cAMP efflux from pinealocytes but strongly inhibited GHRH- stimulated growth hormone (GH) release. Analogs JV-1-50, JV-1-51, and JV-1-52 showed various degrees of VPAC1-R and VPAC2-R antagonistic potency, although also preserving a substantial GHRH antagonistic effect. Analog JV-1- 53 proved to be a highly potent VPAC1 and VPAC2 receptor antagonist, devoid of inhibitory effects on GHRH-evoked GH release. The antagonistic activity of these peptide analogs on processes mediated by receptors for GHRH and VIP was consistent with the binding affinity. The analogs with antagonistic effects on different types of receptors expressed on tumor cells could be utilized for the development of new approaches to treatment of various human cancers.",
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author = "Z. R{\'e}k{\'a}si and Varga, {Jozsef L.} and Schally, {Andrew V.} and Gabor Halmos and Kate Groot and T. Cz{\"o}mp{\"o}ly",
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T1 - Antagonistic actions of analogs related to growth hormone-releasing hormone (GHRH) on receptors for GHRH and vasoactive intestinal peptide on rat pituitary and pineal cells in vitro

AU - Rékási, Z.

AU - Varga, Jozsef L.

AU - Schally, Andrew V.

AU - Halmos, Gabor

AU - Groot, Kate

AU - Czömpöly, T.

PY - 2000/2/1

Y1 - 2000/2/1

N2 - Peptide analogs of growth hormone-releasing hormone (GHRH) can potentially interact with vasoactive intestinal peptide (VIP) receptors (VPAC1-R and VPAC2-R) because of the structural similarities of these two hormones and their receptors. We synthesized four new analogs related to GHRH (JV-1-50, JV-1-51, JV-1-52, and JV-1-53) with decreased GHRH antagonistic activity and increased VIP antagonistic potency. To characterize various peptide analogs for their antagonistic activity on receptors for GHRH and VIP, we developed assay systems based on superfusion of rat pituitary and pineal cells. Receptor-binding affinities of peptides to the membranes of these cells were also evaluated by radioligand competition assays. Previously reported GHRH antagonists JV-1-36, JV-1-38, and JV-1-42 proved to be selective for GHRH receptors, because they did not influence VIP-stimulated VPAC2 receptor-dependent prolactin release from pituitary cells or VPAC1 receptor-dependent cAMP efflux from pinealocytes but strongly inhibited GHRH- stimulated growth hormone (GH) release. Analogs JV-1-50, JV-1-51, and JV-1-52 showed various degrees of VPAC1-R and VPAC2-R antagonistic potency, although also preserving a substantial GHRH antagonistic effect. Analog JV-1- 53 proved to be a highly potent VPAC1 and VPAC2 receptor antagonist, devoid of inhibitory effects on GHRH-evoked GH release. The antagonistic activity of these peptide analogs on processes mediated by receptors for GHRH and VIP was consistent with the binding affinity. The analogs with antagonistic effects on different types of receptors expressed on tumor cells could be utilized for the development of new approaches to treatment of various human cancers.

AB - Peptide analogs of growth hormone-releasing hormone (GHRH) can potentially interact with vasoactive intestinal peptide (VIP) receptors (VPAC1-R and VPAC2-R) because of the structural similarities of these two hormones and their receptors. We synthesized four new analogs related to GHRH (JV-1-50, JV-1-51, JV-1-52, and JV-1-53) with decreased GHRH antagonistic activity and increased VIP antagonistic potency. To characterize various peptide analogs for their antagonistic activity on receptors for GHRH and VIP, we developed assay systems based on superfusion of rat pituitary and pineal cells. Receptor-binding affinities of peptides to the membranes of these cells were also evaluated by radioligand competition assays. Previously reported GHRH antagonists JV-1-36, JV-1-38, and JV-1-42 proved to be selective for GHRH receptors, because they did not influence VIP-stimulated VPAC2 receptor-dependent prolactin release from pituitary cells or VPAC1 receptor-dependent cAMP efflux from pinealocytes but strongly inhibited GHRH- stimulated growth hormone (GH) release. Analogs JV-1-50, JV-1-51, and JV-1-52 showed various degrees of VPAC1-R and VPAC2-R antagonistic potency, although also preserving a substantial GHRH antagonistic effect. Analog JV-1- 53 proved to be a highly potent VPAC1 and VPAC2 receptor antagonist, devoid of inhibitory effects on GHRH-evoked GH release. The antagonistic activity of these peptide analogs on processes mediated by receptors for GHRH and VIP was consistent with the binding affinity. The analogs with antagonistic effects on different types of receptors expressed on tumor cells could be utilized for the development of new approaches to treatment of various human cancers.

KW - Cancer therapy

KW - Growth hormone-releasing hormone and vasoactive intestinal peptide antagonists

KW - Structure-activity relationships

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