Receptors and Neurohormones in Human Pituitary Adenomas

Peillon, F; Dafniet, M. Le; Garnier, P; Brandi, A. M.; Moyse, Emmanuel; Birman, Pascal; Blumberg-Tick, J.; Grouselle, Dominique; Joubert-Bression, D.

doi:10.1159/000181080

Cited by 12 publications

(3 citation statements)

References 16 publications

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“…These results are consistant with the clinical findings obtained with bromocriptine or other DA agonists in patients presenting acromegaly as compared to patients bearing a PRL-secreting adenoma. the demonstration of the release, from the pituitary itself of several neuropetides (Le Dafniet et al, Peillon et al, 1989). We show here the example of SRIH release from GH-secreting adenomas.…”

Section: Relationship Between Cell Response and The Number Of Receptosupporting

confidence: 57%

Perifusion system: its use in the study of the neuroendocrine control of human pituitary tumoral cells

Joubert¹,

Brandi²,

Peillon³

1992

Cell Biol Toxicol

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Regulation of hormone release involves both long term and short term controls, which depends upon which receptor is activated (nuclear or membrane) and upon which stimulating agent is used. When long term regulation is involved, protein synthesis is the major event determining the observed changes in hormone release. When short term regulation is involved, membrane transducing mechanisms are implicated and variations in ion fluxes, adenylate cyclase, phospholipase C, D or A2 activities are immediately followed by changes in hormone release. One same agent may have both long term and short term effects on hormone release as rapid changes in secretory rate, if they last, will end up in changes in synthesis rate.However, in vitro, short and long term regulations need different approaches. Primary culture is well adapted to long term secretory regulation whereas short term regulations need a dynamic approach and the perifusion technique is particularly useful in this case. Indeed, it bathes the tissues in continually fresh medium, thereby eliminating feedback or waste product effects. The tissues can be exposed to various conditions without the artifacts arising from physical manipulations and finally, the time course of any effects produced may be observed.In particular, small changes in release rates which would be blunted in standard culture by the relatively large amount of basal release, will be easily detected.We have used the perifusion system to study the neuroendocrine control of human pituitary tumoral cells, in order to further understand the dysregulation leading to the hypersecretory state of these tumors. Human pituitary tumors are of different types, secreting one or several hormones and nonsecreting. Among the secreting adenomas, we have focused our attention on the prolactinomas, secreting prolactin (PRL), and on the somatotropic adenomas secreting growth hormone (GH). Not only the perifusion system allowed us to study what could be called the "conventional" PRL anf GH release regulation by hypothalamic neuropeptides, it also allowed us to observe differences in the regulation between adenomas of the same cell type and to establish a relationship between the cell response and the number of receptors for a given neuropeptide. Furthermore, we could demonstrate that normal and tumoral pituitary cells produce and release neuropeptides which may interfere with the secretions of pituitary hormones.

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Section: Relationship Between Cell Response and The Number Of Receptosupporting

confidence: 57%

Perifusion system: its use in the study of the neuroendocrine control of human pituitary tumoral cells

Joubert¹,

Brandi²,

Peillon³

1992

Cell Biol Toxicol

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“…EGFR is abundantly expressed in the normal pituitary (38) and, despite initial conflicting reports (39,40), EGFR appears to be expressed in most pituitary tumors at varying levels (8,9,(41)(42)(43)(44). EGF induces PTTG1 in astrocytes (45) and is herein shown to induce Pttg1 mRNA in pituitary TtT/GF cells.…”

Section: Discussionmentioning

confidence: 75%

Mechanisms for Growth Factor-Induced Pituitary Tumor Transforming Gene-1 Expression in Pituitary Folliculostellate TtT/GF Cells

Vlotides

Cruz

Rubinek³

et al. 2006

Molecular Endocrinology

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PTTG1, a securin protein, also behaves as a transforming gene and is overexpressed in pituitary tumors. Because pituitary folliculostellate (FS) cells regulate pituitary tumor growth factors by paracrine mechanisms, epidermal growth factor (EGF) receptor (EGFR)-mediated PTTG1 expression and cell proliferation was tested in pituitary FS TtT/GF cells. EGFR ligands caused up to 3-fold induction of Pttg1 mRNA expression, enhanced proliferating cell nuclear antigen, and increased entry of G0/1-arrested cells into S-phase. PTTG binding factor mRNA expression was not altered. EGF-induced Pttg1 expression and cell proliferation was abolished by preincubation of TtT/GF cells with EGFR inhibitors AG1478 and gefitinib. Phosphatidylinositol 3 kinase, protein kinase C, and MAPK, but not c-Jun N-terminal kinase and Janus activating kinase signaling regulated EGF-induced Pttg1, as well as proliferating cell nuclear antigen mRNA expression and entry into S-phase. EGF-induced EGFR and ERK1/2 phosphorylation was followed by rapid MAPK kinase/ERK kinase-dependent activation of Elk-1 and c-Fos. EGF-induced Pttg1 expression peaked at the S-G2 transition and declined thereafter. Pttg1 cell cycle dependency was confirmed by suppression of EGF-induced Pttg1 mRNA by blockade of cells in early S-phase. The results show that PTTG1 and its binding protein PTTG binding factor are expressed in pituitary FS TtT/GF cells. EGFR ligands induce PTTG1 and regulate S-phase, mediated by phosphatidylinositol 3 kinase, protein kinase C, and MAPK pathways. PTTG1 is therefore a target for EGFR-mediated paracrine regulation of pituitary cell growth.

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“…Clinical evaluation of the efficacy of dopaminergic therapy is difficult because of the absence of reliable hormonal markers and the fact that it is impossible to select those NFPA patients with dopamine D2 receptor-positive tumours. In general, NFPA show a lower dopamine D2 receptor density than PRL-secreting adenomas (Serri et al, 1984;Koga et al, 1987;Muhr et al, 1988;Peillon et al, 1989). Future studies are needed to validate whether SPECT with 123 I-IBZM might be of assistance in the differential diagnosis of tumours in the pituitary region.…”

Section: Discussionmentioning

confidence: 97%

In vivo imaging of pituitary tumours using a radiolabelled dopamine D2 receptor radioligand

Herder

Reijs

Kwekkeboom

et al. 1996

Clinical Endocrinology

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Receptors and Neurohormones in Human Pituitary Adenomas

Cited by 12 publications

References 16 publications

Perifusion system: its use in the study of the neuroendocrine control of human pituitary tumoral cells

Perifusion system: its use in the study of the neuroendocrine control of human pituitary tumoral cells

Mechanisms for Growth Factor-Induced Pituitary Tumor Transforming Gene-1 Expression in Pituitary Folliculostellate TtT/GF Cells

In vivo imaging of pituitary tumours using a radiolabelled dopamine D2 receptor radioligand

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