Growth Hormone (GH)-Releasing Factor Does Not Regulate GH Release or GH mRNA Levels in GH<sub>3</sub>Cells*

Zeytin, Füsûn N.; Gick, Gregory; Brazeau, Paul; Ling, Nicholas; McLaughlin, Marilyn; Bancroft, Carter

doi:10.1210/endo-114-6-2054

Cited by 45 publications

(14 citation statements)

References 17 publications

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“…Because GH3 cells do not possess receptors for GHRH (Zeytin et al 1984), stably transfected GH3 cells with hGHRHR (GH3-GHRHR) cells were established. RT-PCR and western blot analysis were performed to assess hGHRHR expression in 4 clones obtained.…”

Section: Activation Of Gh Gene By Cxcl12 In Gh3-ghrhr and Primary Ratmentioning

confidence: 99%

Functional expression of CXCR4 in somatotrophs: CXCL12 activates GH gene, GH production and secretion, and cellular proliferation

Lee

Kim

Lee

2008

Journal of Endocrinology

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The interaction of chemokine (C-X-C motif) ligand 12 (CXCL12) and its receptor CXCR4 may play an important role in the regulation of anterior pituitary function. In this study, we investigated the expression of CXCL12 and CXCR4 and their role in normal rat pituitary and GH-producing GH3 tumor cell line. RT-PCR analysis and immunohistochemistry revealed that CXCR4 was expressed in normal rat anterior pituitary and GH3 tumor cells. Double immunofluorescent staining showed the complete colocalization of CXCR4 with GH in rat pituitary, indicating that CXCR4 is specifically expressed in rat somatotrophs. Using rat primary pituitary cell cultures and GH releasing hormone receptor expressing stable GH3 cells (GH3-GHRHR), we evaluated the function of CXCL12 compared with GHRH.CXCL12 stimulated GH gene activation in both primary rat anterior pituitary cells and GH3-GHRHR cells. CXCL12 also stimulated GH secretion from primary rat pituitary cells in a dose-dependant manner. BrdU incorporation was increased in response to CXCL12 addition in GH3 cell culture, indicating CXCL12-induced cell proliferation. CXCL12-dependent phosphorylation of ERK1/2 was also confirmed by western blot analysis, supporting the evidence that MAPK is an intracellular mediator of CXCL12/CXCR4 interaction in GH3 cell proliferation. In conclusion, these results indicate that CXCL12/CXCR4 interaction plays an important role in GH production, secretion, and the proliferation of somatotrophs.

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Section: Activation Of Gh Gene By Cxcl12 In Gh3-ghrhr and Primary Ratmentioning

confidence: 99%

Functional expression of CXCR4 in somatotrophs: CXCL12 activates GH gene, GH production and secretion, and cellular proliferation

Lee

Kim

Lee

2008

Journal of Endocrinology

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“…To further examine the role of Cdk4 in proliferation of the somatotroph lineage in an environment without a complex endocrine network, we used rat somato/lactotroph GH3 cells. This immortalized cell line exhibits characteristics of both somatotroph and lactotroph and expresses detectable levels of GH and PRL, whereas it shows minimum expression of GHRH receptors (22,23). Thus, to study GHRH-mediated proliferation in vitro, we restored the expression of GHRH receptors in GH3 cells by Ad GHRH-R (15).…”

Section: Cdk4 Is Dispensable For Prenatal Pituitary Development Andmentioning

confidence: 99%

Cdk4 Is Indispensable for Postnatal Proliferation of the Anterior Pituitary

Jirawatnotai¹,

Aziyu²,

Osmundson³

et al. 2004

Journal of Biological Chemistry

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“…The GH3 pituitary cells have been reported to possess receptors for somatostatin (20) and to be unresponsive to GH-RH stimulation (21). Interestingly, the somatostatin analogs used in this study did not inhibit tumor growth, but rather enhanced it under our conditions.…”

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confidence: 49%

Inhibition of growth of a prolactin and growth hormone-secreting pituitary tumor in rats by D-tryptophan-6 analog of luteinizing hormone-releasing hormone.

Torres‐Alemán¹,

Redding²

1985

Proc. Natl. Acad. Sci. U.S.A.

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The effect of long-term administration of analogs of luteinizing hormone-releasing hormone (LH-RH) and somatostatin on the growth of the growth hormone (GH)-and prolactin (PRL)-secreting rat pituitary GH3 tumor was investigated. Daily administration of tg/day) (Oss, Holland). Somatostatin analog cyclo(Pro-Phe-DTrp-Lys-Thr-Phe) (Veber cyclic hexapeptide) (12) was synthesized in our laboratory or supplied by J. Sandow and R. Geiger (Hoechst, Frankfurt M, FRG). Somatostatin analog D-Phe-Cys-Phe-t-Trp-Lys-Thr-Cys-Thr-NH2 related to the octapeptide of Bauer (13) was synthesized in our laboratory by solid-phase methods described previously (14).Female Wistar/Furth rats (80-100 g, Harlan SpragueDawley, Indianapolis, IN) were inoculated s.c. in the scapular region with OH3 pituitary tumor cells (obtained from the American Type Culture Collection). The animals were housed 5-7 per cage in a temperature-and light-controlled room. Five to seven animals were used per experimental group. In the first experiment, the treatment with peptides was started before tumors appeared, while in subsequent experiments, peptide administration was initiated when 50-100% of the animals showed well-developed tumors. Tumors were measured weekly with microcalipers and tumor volumes were calculated as described (7). Experiment I. Three days after inoculation of 1 X 106 GH3

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Growth Hormone (GH)-Releasing Factor Does Not Regulate GH Release or GH mRNA Levels in GH₃Cells*

Cited by 45 publications

References 17 publications

Functional expression of CXCR4 in somatotrophs: CXCL12 activates GH gene, GH production and secretion, and cellular proliferation

Functional expression of CXCR4 in somatotrophs: CXCL12 activates GH gene, GH production and secretion, and cellular proliferation

Cdk4 Is Indispensable for Postnatal Proliferation of the Anterior Pituitary

Inhibition of growth of a prolactin and growth hormone-secreting pituitary tumor in rats by D-tryptophan-6 analog of luteinizing hormone-releasing hormone.

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Growth Hormone (GH)-Releasing Factor Does Not Regulate GH Release or GH mRNA Levels in GH3Cells*

Cited by 45 publications

References 17 publications

Functional expression of CXCR4 in somatotrophs: CXCL12 activates GH gene, GH production and secretion, and cellular proliferation

Functional expression of CXCR4 in somatotrophs: CXCL12 activates GH gene, GH production and secretion, and cellular proliferation

Cdk4 Is Indispensable for Postnatal Proliferation of the Anterior Pituitary

Inhibition of growth of a prolactin and growth hormone-secreting pituitary tumor in rats by D-tryptophan-6 analog of luteinizing hormone-releasing hormone.

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Growth Hormone (GH)-Releasing Factor Does Not Regulate GH Release or GH mRNA Levels in GH₃Cells*