Inhibitory effects of antagonistic analogs of GHRH on GH3 pituitary cells overexpressing the human GHRH receptor

M. Kovacs, A. V. Schally, Eunjig Lee, R. Busto, P. Armatis, K. Groot, J. L. Varga

Research output: Contribution to journalReview article

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Abstract

GH3 rat pituitary tumor cells produce GH and prolactin (PRL), but lack the GHRH receptor (GHRH-R). We expressed human GHRH-R (hGHRH-R) in GH3 cells using recombinant adenoviral vectors and studied the effects of GHRH antagonists. The mRNA expression of the GHRH-R gene in the cells was demonstrated by RT-PCR. An exposure of the GH3 cells infected with hGHRH-R to 10-10, 10-9 and 10-8 M hGHRH for 1 or 2 h in culture caused a dose-dependent elevation of the intracellular cAMP concentration and the cAMP efflux. Exposure to hGHRH also elicited dose-dependent increases in GH and PRL secretion from these cells. Neither the uninfected nor the antisense hGHRH-R-infected control cells exhibited cAMP, GH and PRL responses to GHRH stimulation. GHRH antagonists JV-1-38 and JV-1-36 applied at 3 × 10-8 M for 3 h, together with 10-9 M GHRH, significantly inhibited the GHRH-stimulated cAMP efflux from the hGHRH-R-infected cells by 36 and 80% respectively. The more potent antagonist JV-1-36 also decreased the intracellular cAMP levels in these cells by 55%. Exposure to JV-1-36 for 1 h nullified the stimulatory effect of GHRH on GH secretion and significantly inhibited it by 64 and 77% after 2 and 3 h respectively. In a superfusion system, GHRH at 10-10, 10-9 and 10-8 M concentrations induced prompt and dose-related high cAMP responses and smaller increases in the spontaneous GH secretion of the hGHRH-R-infected cells. Antagonists JV-1-36 and JV-1-38 applied at 3 × 10-8 M for 15 min, together with 10-9 M GHRH, inhibited the GHRH-stimulated cAMP response by 59 and 35% respectively. This work demonstrates that GHRH antagonists can effectively inhibit the actions of GHRH on the hGHRH-R. Our results support the view that this class of compounds would be active clinically.

Original languageEnglish
Pages (from-to)425-434
Number of pages10
JournalJournal of Endocrinology
Volume175
Issue number2
DOIs
Publication statusPublished - 2002 Nov 1

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Prolactin
somatotropin releasing hormone receptor
Pituitary Neoplasms
Polymerase Chain Reaction
Messenger RNA
JV 1-36
Genes
JV 1-38
galantide

All Science Journal Classification (ASJC) codes

  • Endocrinology, Diabetes and Metabolism
  • Endocrinology

Cite this

Kovacs, M. ; Schally, A. V. ; Lee, Eunjig ; Busto, R. ; Armatis, P. ; Groot, K. ; Varga, J. L. / Inhibitory effects of antagonistic analogs of GHRH on GH3 pituitary cells overexpressing the human GHRH receptor. In: Journal of Endocrinology. 2002 ; Vol. 175, No. 2. pp. 425-434.
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abstract = "GH3 rat pituitary tumor cells produce GH and prolactin (PRL), but lack the GHRH receptor (GHRH-R). We expressed human GHRH-R (hGHRH-R) in GH3 cells using recombinant adenoviral vectors and studied the effects of GHRH antagonists. The mRNA expression of the GHRH-R gene in the cells was demonstrated by RT-PCR. An exposure of the GH3 cells infected with hGHRH-R to 10-10, 10-9 and 10-8 M hGHRH for 1 or 2 h in culture caused a dose-dependent elevation of the intracellular cAMP concentration and the cAMP efflux. Exposure to hGHRH also elicited dose-dependent increases in GH and PRL secretion from these cells. Neither the uninfected nor the antisense hGHRH-R-infected control cells exhibited cAMP, GH and PRL responses to GHRH stimulation. GHRH antagonists JV-1-38 and JV-1-36 applied at 3 × 10-8 M for 3 h, together with 10-9 M GHRH, significantly inhibited the GHRH-stimulated cAMP efflux from the hGHRH-R-infected cells by 36 and 80{\%} respectively. The more potent antagonist JV-1-36 also decreased the intracellular cAMP levels in these cells by 55{\%}. Exposure to JV-1-36 for 1 h nullified the stimulatory effect of GHRH on GH secretion and significantly inhibited it by 64 and 77{\%} after 2 and 3 h respectively. In a superfusion system, GHRH at 10-10, 10-9 and 10-8 M concentrations induced prompt and dose-related high cAMP responses and smaller increases in the spontaneous GH secretion of the hGHRH-R-infected cells. Antagonists JV-1-36 and JV-1-38 applied at 3 × 10-8 M for 15 min, together with 10-9 M GHRH, inhibited the GHRH-stimulated cAMP response by 59 and 35{\%} respectively. This work demonstrates that GHRH antagonists can effectively inhibit the actions of GHRH on the hGHRH-R. Our results support the view that this class of compounds would be active clinically.",
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Inhibitory effects of antagonistic analogs of GHRH on GH3 pituitary cells overexpressing the human GHRH receptor. / Kovacs, M.; Schally, A. V.; Lee, Eunjig; Busto, R.; Armatis, P.; Groot, K.; Varga, J. L.

In: Journal of Endocrinology, Vol. 175, No. 2, 01.11.2002, p. 425-434.

Research output: Contribution to journalReview article

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T1 - Inhibitory effects of antagonistic analogs of GHRH on GH3 pituitary cells overexpressing the human GHRH receptor

AU - Kovacs, M.

AU - Schally, A. V.

AU - Lee, Eunjig

AU - Busto, R.

AU - Armatis, P.

AU - Groot, K.

AU - Varga, J. L.

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N2 - GH3 rat pituitary tumor cells produce GH and prolactin (PRL), but lack the GHRH receptor (GHRH-R). We expressed human GHRH-R (hGHRH-R) in GH3 cells using recombinant adenoviral vectors and studied the effects of GHRH antagonists. The mRNA expression of the GHRH-R gene in the cells was demonstrated by RT-PCR. An exposure of the GH3 cells infected with hGHRH-R to 10-10, 10-9 and 10-8 M hGHRH for 1 or 2 h in culture caused a dose-dependent elevation of the intracellular cAMP concentration and the cAMP efflux. Exposure to hGHRH also elicited dose-dependent increases in GH and PRL secretion from these cells. Neither the uninfected nor the antisense hGHRH-R-infected control cells exhibited cAMP, GH and PRL responses to GHRH stimulation. GHRH antagonists JV-1-38 and JV-1-36 applied at 3 × 10-8 M for 3 h, together with 10-9 M GHRH, significantly inhibited the GHRH-stimulated cAMP efflux from the hGHRH-R-infected cells by 36 and 80% respectively. The more potent antagonist JV-1-36 also decreased the intracellular cAMP levels in these cells by 55%. Exposure to JV-1-36 for 1 h nullified the stimulatory effect of GHRH on GH secretion and significantly inhibited it by 64 and 77% after 2 and 3 h respectively. In a superfusion system, GHRH at 10-10, 10-9 and 10-8 M concentrations induced prompt and dose-related high cAMP responses and smaller increases in the spontaneous GH secretion of the hGHRH-R-infected cells. Antagonists JV-1-36 and JV-1-38 applied at 3 × 10-8 M for 15 min, together with 10-9 M GHRH, inhibited the GHRH-stimulated cAMP response by 59 and 35% respectively. This work demonstrates that GHRH antagonists can effectively inhibit the actions of GHRH on the hGHRH-R. Our results support the view that this class of compounds would be active clinically.

AB - GH3 rat pituitary tumor cells produce GH and prolactin (PRL), but lack the GHRH receptor (GHRH-R). We expressed human GHRH-R (hGHRH-R) in GH3 cells using recombinant adenoviral vectors and studied the effects of GHRH antagonists. The mRNA expression of the GHRH-R gene in the cells was demonstrated by RT-PCR. An exposure of the GH3 cells infected with hGHRH-R to 10-10, 10-9 and 10-8 M hGHRH for 1 or 2 h in culture caused a dose-dependent elevation of the intracellular cAMP concentration and the cAMP efflux. Exposure to hGHRH also elicited dose-dependent increases in GH and PRL secretion from these cells. Neither the uninfected nor the antisense hGHRH-R-infected control cells exhibited cAMP, GH and PRL responses to GHRH stimulation. GHRH antagonists JV-1-38 and JV-1-36 applied at 3 × 10-8 M for 3 h, together with 10-9 M GHRH, significantly inhibited the GHRH-stimulated cAMP efflux from the hGHRH-R-infected cells by 36 and 80% respectively. The more potent antagonist JV-1-36 also decreased the intracellular cAMP levels in these cells by 55%. Exposure to JV-1-36 for 1 h nullified the stimulatory effect of GHRH on GH secretion and significantly inhibited it by 64 and 77% after 2 and 3 h respectively. In a superfusion system, GHRH at 10-10, 10-9 and 10-8 M concentrations induced prompt and dose-related high cAMP responses and smaller increases in the spontaneous GH secretion of the hGHRH-R-infected cells. Antagonists JV-1-36 and JV-1-38 applied at 3 × 10-8 M for 15 min, together with 10-9 M GHRH, inhibited the GHRH-stimulated cAMP response by 59 and 35% respectively. This work demonstrates that GHRH antagonists can effectively inhibit the actions of GHRH on the hGHRH-R. Our results support the view that this class of compounds would be active clinically.

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