The Gonadotropin-Releasing Hormone Receptor: Signals Involved in Gonadotropin Secretion and Biosynthesis

Dan-Cohen, Hana; Ben-Menahem, David; Naor, Zvi

doi:10.1159/000181488

Cited by 6 publications

(1 citation statement)

References 56 publications

(65 reference statements)

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“…The PKC inhibitors staurosporine and GF 109203X exerted a dose-related inhibition upon GnRHa elevation of a-subunit mRNA levels with IC50 values of 4 and 90 nM respectively, in good agreement with the concentrations known to inhibit PKC-mediated responses in other cellular systems [26,27]. The second approach utilized the phenomenon of down-regulation of endogenous PKC by prolonged exposure to PMA [31,32]. Indeed down-regulation of PKC in aT3-1 cells resulted in about 90% loss of PKC activity accompanied by inhibition of GnRH and PMA elevation of a-subunit mRNA levels.…”

Section: Discussionmentioning

confidence: 71%

Mechanism of action of gonadotropin-releasing hormone upon gonadotropin α-subunit mRNA levels in the α T3-1 cell line: role of Ca2+ and protein kinase C

Ben-Menahem

Shraga-Levine

Mellon

et al. 1995

Biochemical Journal

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Addition of [D-Trp6]gonadotropin-releasing hormone (GnRHa) to alpha T3-1 cells induced a very rapid response upon gonadotropin alpha-subunit mRNA which was detected after 30-60 min and was abolished by pretreatment with actinomycin D. A similar response was obtained with the protein kinase C (PKC) activator phorbol 12-myristate 13-acetate (PMA), or the Ca2+ ionophore, ionomycin. GnRHa (10 nM) also stimulated a secondary rise in alpha-subunit mRNA levels between 12 and 24 h of incubation. No additivity was obtained (at 60 min) upon the combined addition of GnRHa and PMA, GnRHa and ionomycin, or PMA and ionomycin. The effect of GnRHa upon alpha-subunit mRNA was blocked by the PKC inhibitors staurosporine or GF 109203X. Down-regulation of endogenous PKC activity resulted in inhibition of the stimulatory effect of gonadotropin-releasing hormone (GnRH), PMA and ionomycin. Removal of extra-cellular Ca2+ abolished the effect of GnRHa and PMA upon alpha-subunit mRNA levels. Interestingly PMA and ionomycin had no effect on alpha-subunit mRNA levels at 24 h of incubation; however, the combined addition of the drugs mimicked the late phase of GnRHa (10 nM) action. The data provide evidence that PKC and Ca2+ are involved in mediating the early and the late responses of GnRHa upon alpha-subunit mRNA elevation and that differential cross-talk exists between the messengers.

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Section: Discussionmentioning

confidence: 71%

Mechanism of action of gonadotropin-releasing hormone upon gonadotropin α-subunit mRNA levels in the α T3-1 cell line: role of Ca2+ and protein kinase C

Ben-Menahem

Shraga-Levine

Mellon

et al. 1995

Biochemical Journal

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Signal transduction of the gonadotropin releasing hormone (GnRH) receptor: Cross-talk of calcium, protein kinase C (PKC), and arachidonic acid

et al. 1995

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1. The decapeptide neurohormone gonadotropin releasing hormone (GnRH) is the first key hormone of the reproductive system. Produced in the hypothalamus, GnRH is released in a pulsatile manner into the hypophysial portal system to reach the anterior pituitary and stimulates the release and synthesis of the gonadotropin hormones LH and FSH. GnRH, a Ca2+ mobilizing ligand, binds to its respective binding protein, which is a member of the seven transmembrane domain receptor family and activates a G-protein (Gq). 2. The alpha subunit of Gq triggers enhanced phosphoinositide turnover and the elevation of multiple second messengers required for gonadotropin release and biosynthesis. 3. The messenger molecules IP3, diacylglycerol, Ca2+, protein kinase C, arachidonic acid and leukotriene C4 cross-talk in a complex networks of signaling, culminating in gonadotropin release and gene expression.

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Molecular Mechanisms of the Regulation of Gonadotropin Gene Expression by Gonadotropin-releasing Hormone

Kaiser

1998

Molecules and Cells

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The Gonadotropin-Releasing Hormone Receptor: Signals Involved in Gonadotropin Secretion and Biosynthesis

Cited by 6 publications

References 56 publications

Mechanism of action of gonadotropin-releasing hormone upon gonadotropin α-subunit mRNA levels in the α T3-1 cell line: role of Ca2+ and protein kinase C

Mechanism of action of gonadotropin-releasing hormone upon gonadotropin α-subunit mRNA levels in the α T3-1 cell line: role of Ca2+ and protein kinase C

Signal transduction of the gonadotropin releasing hormone (GnRH) receptor: Cross-talk of calcium, protein kinase C (PKC), and arachidonic acid

Molecular Mechanisms of the Regulation of Gonadotropin Gene Expression by Gonadotropin-releasing Hormone

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