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Musha S, Yoshida S, Murakami S, Kojima R, Deai M, Saso N, Mogi C, Sato K, Okajima F, Tomura H. Involvement of GPR4 in increased growth hormone and prolactin expressions by extracellular acidification in MtT/S cells. J Reprod Dev 2020; 66:175-180. [PMID: 31956173 PMCID: PMC7175386 DOI: 10.1262/jrd.2019-159] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Hormone-secreting pituitary adenomas show unregulated hormonal hypersecretion and cause hyperpituitarism. However, the mechanism of the unregulated hormone production and secretion has not
yet been fully elucidated. Solid tumors show reduced extracellular pH, partly due to lactate secretion from anaerobic glycolysis. It is known that extracellular acidification affects hormone
secretion. However, whether and how the extracellular acidification influences the unregulated hormone production and secretion remain unknown. In the present study, we found that
GPR4, a proton-sensing G protein-coupled receptor, was highly expressed in MtT/S cells, a growth hormone-producing and prolactin-producing pituitary tumor cell line. When
we reduced the extracellular pH, growth hormone and prolactin mRNA expressions increased in the cells. Both increased expressions were partially suppressed
by a GPR4 antagonist. We also found that extracellular acidification enhanced growth hormone-releasing factor-induced growth hormone secretion from MtT/S cells. These results suggest that
GPR4 may play a role in hypersecretion of the hormone from hormone-producing pituitary tumors. A GPR4 antagonist will be a useful tool for preventing the hypersecretion.
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Affiliation(s)
- Shiori Musha
- Laboratory of Cell Signaling Regulation, Department of Life Sciences, School of Agriculture, Meiji University, Kawasaki 214-8571, Japan
| | - Saishu Yoshida
- Department of Biochemistry, Jikei University School of Medicine, Tokyo 105-8461, Japan
| | - Syo Murakami
- Laboratory of Cell Signaling Regulation, Department of Life Sciences, School of Agriculture, Meiji University, Kawasaki 214-8571, Japan
| | - Ryotaro Kojima
- Laboratory of Cell Signaling Regulation, Department of Life Sciences, School of Agriculture, Meiji University, Kawasaki 214-8571, Japan
| | - Masahito Deai
- Laboratory of Cell Signaling Regulation, Department of Life Sciences, School of Agriculture, Meiji University, Kawasaki 214-8571, Japan
| | - Naoshi Saso
- Laboratory of Cell Signaling Regulation, Department of Life Sciences, School of Agriculture, Meiji University, Kawasaki 214-8571, Japan
| | - Chihiro Mogi
- Laboratory of Integrated Signaling Systems, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi 371-8512, Japan
| | - Koichi Sato
- Laboratory of Medical Neuroscience, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi 371-8512, Japan
| | - Fumikazu Okajima
- Laboratory of Pathophysiology, Faculty of Pharmacy, Aomori University, Aomori 030-0943, Japan
| | - Hideaki Tomura
- Laboratory of Cell Signaling Regulation, Department of Life Sciences, School of Agriculture, Meiji University, Kawasaki 214-8571, Japan.,Institute of Endocrinology, Meiji University, Kawasaki 214-8571, Japan
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Curtin BF, Pal N, Gordon RK, Nambiar MP. Forskolin, an inducer of cAMP, up-regulates acetylcholinesterase expression and protects against organophosphate exposure in neuro 2A cells. Mol Cell Biochem 2006; 290:23-32. [PMID: 16924422 DOI: 10.1007/s11010-005-9084-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2005] [Accepted: 11/22/2005] [Indexed: 11/25/2022]
Abstract
Bioscavenger prophylactic therapy using purified human acetylcholinesterase (AChE) or butylcholinesterase (BChE) is a promising treatment for future protection against chemical warfare nerve agent exposure. Potential immune response due to the complex structure of cholinesterases, mutations, post-translational modifications, and genetic variation is a limiting factor against purified enzyme therapy. We investigated an alternative bioscavenger approach using forskolin, an inducer of intracellular cyclic AMP (cAMP), which activates AChE promoter and up-regulates its expression. A mouse neuronal cell line, Neuro 2A, was treated with various doses of forskolin and analysis of the expressed enzyme indicates that the AChE activity was significantly increased in cells exposed to repeated administration of the drug every other day for 7-10 days. Cholinesterase enzyme assays showed that the enzyme activity was increased approximately 2-fold for the extracellular enzyme and 3-fold for the intracellular enzyme. The optimal dose found for extracellular enzyme production was 12-24 microM forskolin, while the optimal dose for intracellular was 12 microM. In parallel with the rise in the AChE level, the morphology of forskolin-treated cells showed neurite growth with increasing doses. Forskolin treatment protects Neuro 2A cells from diisopropylflurophophate (DFP), a surrogate of the organophosphate chemical warfare agents soman and sarin, induced toxicity in Neuro 2A cells. These results indicate that transcriptional inducers, such as forskolin, can sufficiently up-regulate cellular AChE production and protect cells against organophosphate toxicity.
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Affiliation(s)
- Bryan F Curtin
- Department of Biochemical Pharmacology, Division of Biochemistry, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD 20910-7500, USA
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Ooi GT, Tawadros N, Escalona RM. Pituitary cell lines and their endocrine applications. Mol Cell Endocrinol 2004; 228:1-21. [PMID: 15541569 DOI: 10.1016/j.mce.2004.07.018] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2004] [Accepted: 07/15/2004] [Indexed: 10/26/2022]
Abstract
The pituitary gland is an important component of the endocrine system, and together with the hypothalamus, exerts considerable influence over the functions of other endocrine glands. The hypothalamus either positively or negatively regulates hormonal productions in the pituitary through its release of various trophic hormones which act on specific cell types in the pituitary to secrete a variety of pituitary hormones that are important for growth and development, metabolism, reproductive and nervous system functions. The pituitary is divided into three sections-the anterior lobe which constitute the majority of the pituitary mass and is composed primarily of five hormone-producing cell types (thyrotropes, lactotropes, corticotropes, somatotropes and gonadotropes) each secreting thyrotropin, prolactin, ACTH, growth hormone and gonadotropins (FSH and LH) respectively. There is also a sixth cell type in the anterior lobe-the non-endocrine, agranular, folliculostellate cells. The intermediate lobe produces melanocyte-stimulating hormone and endorphins, whereas the posterior lobe secretes anti-diuretic hormone (vasopressin) and oxytocin. Representative cell lines of all the six cell types of the anterior pituitary have been established and have provided valuable information on genealogy of the various cell lineages, endocrine feedback control of hormone synthesis and secretions, intrapituitary interactions between the various cell types, as well as the role of specific transcription factors that determine each differentiated cell phenotype. In this review, we will discuss the morphology and function of the cell types that make up the anterior pituitary, and the characteristics of the various functional anterior pituitary cell systems that have been established to be representative of each anterior pituitary cell lineage.
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Affiliation(s)
- Guck T Ooi
- Prince Henry's Institute of Medical Research, Monash Medical Centre, Block E, Level 4, 246 Clayton Road, Clayton, Victoria 3168, Australia.
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Iwasaki Y, Morishita M, Asai M, Onishi A, Yoshida M, Oiso Y, Inoue K. Effects of hormones targeting nuclear receptors on transcriptional regulation of the growth hormone gene in the MtT/S rat somatotrope cell line. Neuroendocrinology 2004; 79:229-36. [PMID: 15240998 DOI: 10.1159/000078787] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2004] [Accepted: 03/29/2004] [Indexed: 11/19/2022]
Abstract
We have examined the effects of nuclear receptor hormones such as glucocorticoid, gonadal steroid hormones, thyroid hormone and retinoids on the transcriptional regulation of the 5'-promoter activity of growth hormone (GH) gene using the MtT/S rat pure somatotrope cell line or MtT/SGL, a subclone of MtT/S in which the rat GH gene 5'-promoter (1.7 Kb)-luciferase fusion gene was stably incorporated. RT-PCR analyses revealed that receptors for all the hormones except androgen receptor were expressed in the cell line. Triiodothyronine (T(3), 10 nM) transiently but significantly stimulated the promoter activity of GH gene, whereas retinoic acids (9-cis and all-trans, both 1 microM) showed sustained stimulation. There were no additive effects among the T(3), all-trans, and9-cis retinoic acids. Synthetic glucocorticoid hormone dexamethasone (100 nM) showed an inhibitory effect but, interestingly, significantly enhanced T(3)-stimulated GH promoter activity during long-term incubation. Among the gonadal steroid hormones tested, estradiol and estriol had significant stimulatory effects, and deletion analysis showed that the estrogen effect was maintained with the shortest construct examined (-150 to +6, +1 denotes the transcription start site). These results suggest that thyroid hormone and retinoids stimulate the transcription of GH gene, probably through a common response element, whereas glucocorticoid has both negative and positive effects on GH expression, depending on the combination with other hormones and the time of exposure. Estrogens also have direct stimulatory effects through the proximal promoter region of GH gene.
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Affiliation(s)
- Yasumasa Iwasaki
- Department of Clinical Pathophysiology, Nagoya University Graduate School of Medicine and Hospital, Nagoya, Japan.
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