scholarly journals What is the role of melatonin within the anterior pituitary?

2001 ◽  
Vol 170 (3) ◽  
pp. 493-501 ◽  
Author(s):  
DG Hazlerigg
Keyword(s):  
Anterior Pituitary ◽  
Cellular Level ◽  
Prolactin Secretion ◽  
Receptor Expression ◽  
Melatonin Receptors ◽  
Seasonal Effects ◽  
Pars Tuberalis ◽  
Melatonin Receptor ◽  
Functional Studies

The pineal hormone, melatonin, is uniquely defined by its role as hormonal time, but the processes whereby cells extract temporal information from the melatonin signal are not understood. Melatonin receptors are expressed in the pars tuberalis (PT) and, during fetal and perinatal life, in the pars distalis (PD). Functional studies suggest that the PT mediates the seasonal effects of melatonin on prolactin secretion, whilst the PD may be involved in photoperiodic programming of the developing gonadotrophic axis. To understand these effects at the cellular level we need to know the phenotype of melatonin-responsive cells. This review summarises current understanding in this area, and highlights present shortcomings. A case is presented for exploring the hypothesis that there is a functional association between melatonin receptor expression and cell differentiation in the anterior pituitary.

scholarly journals The mt1 Melatonin Receptor and RORβ Receptor Are Co-localized in Specific TSH-immunoreactive Cells in the Pars Tuberalis of the Rat Pituitary

2002 ◽  
Vol 50 (12) ◽  
pp. 1647-1657 ◽  
Author(s):  
Paul Klosen ◽  
Christele Bienvenu ◽  
Olivier Demarteau ◽  
Hugues Dardente ◽  
Hilda Guerrero ◽  
...  
Keyword(s):  
Cell Types ◽  
Orphan Receptor ◽  
Seasonal Effects ◽  
Pars Tuberalis ◽  
Melatonin Receptor ◽  
Functional Studies ◽  
Rat Pituitary ◽  
Mt1 Melatonin Receptor

The pars tuberalis (PT) of the pituitary represents an important target site for the time-pacing pineal hormone melatonin because it expresses a large number of mt1 receptors. Functional studies suggest that the PT mediates the seasonal effects of melatonin on prolactin (PRL) secretion. The aim of this study was the characterization of the pheno-type of melatonin-responsive cells. Furthermore, we determined whether RORβ, a retinoid orphan receptor present in the PT, was co-expressed in the same cells. We combined nonradioactive in situ hybridization (ISH) with hapten-labeled riboprobes for detection of the receptors and immunocytochemistry (ICC) for detection of αGSU (α-glycoprotein subunit), βTSH, βFSH, βLH, GH, PRL, and ACTH. Expression of mt1 mRNA was found in small round cells, co-localized with αGSU and βTSH. However, not all βTSH-containing cells expressed mt1 mRNA. The distribution of mt1- and RORβ-positive cells appeared to overlap, although more cells were labeled for RORβ than for mt1. Gonadotrophs, as well as other pars distalis cell types, were never labeled for mt1 melatonin receptor. Therefore, this study identifies the “specific” cells of the PT as the mt1 melatonin receptor-expressing cells.

The role of neurokinin A and its receptor in the regulation of prolactin secretion by the anterior pituitary of cyclic pigs

2020 ◽  
Vol 55 (5) ◽  
pp. 604-612
Author(s):  
Wioleta Czelejewska ◽  
Agata Zmijewska ◽  
Mariusz Dziekonski ◽  
Stanislaw Okrasa
Keyword(s):  
Anterior Pituitary ◽  
Prolactin Secretion ◽  
Neurokinin A

Chronobiological features of melatonin receptors (MT1) expression in breast cancer cells.

2019 ◽  
Vol 37 (15_suppl) ◽  
pp. e12581-e12581
Author(s):  
Alexandre Tavartkiladze ◽  
Ani Gvajaia ◽  
Pati Revazishvili
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Venous Blood ◽  
Receptor Expression ◽  
Melatonin Receptors ◽  
Breast Cancer Patients ◽  
Melatonin Receptor ◽  
Circadian Expression ◽  
Immunocytochemical Method

e12581 Background: According to WHO data, Breast Cancer is the most prevalent malignancy in women. The biological role of Melatonin in the etiology and pathogenesis of the tumour disease has already been approved by a number of research studies. The purpose of our investigation was the assessment of features of Melatonin receptor circadian expression in circulating tumour cells of breast cancer (CTCs). Methods: We observed 34 patients (aged 36-68) with breast cancer (various immunophenotypes). CTCs were separated from patients’ venous blood every third day, in 02:00-04:00 pm and in 02:00-04:00 am intervals. The cells were taken from each patient 4 times. On CTCs, MT1 – receptor expression was assessed using immunocytochemical method. Results: Results of the study revealed that Melatonin receptor expression in breast cancer patients is characterised by the noticable circadian rhythmics. MT1–receptor expression peak by CTCs was detected at 02:00-04:00 am i.e. at night. The less aggressive tumor the higher is the extent of the receptor expression (density). Respectively, in hormone dependent and Her2/neu (negative) tumors the highest expression of the MT1–receptor occurs in hormone dependent and Her2/neu(positive) tumors–medium expression and in triple negative breast Cancer (TNBC) cells–the lowest expression, while in some TNBC–circulating tumor cells MT1 receptor expression has not been detected at all. Conclusions: Hence, based on our the results, we can conclude that Melatonin as the expression of main biochemical marker receptors of bio-rhythms in breast cancer cells, has highly expressed chronobiological nature and directly correlates with histological types of tumor, that provides conditions for the development of new chronotherapeutic strategies in breast cancer treatment.

Biological Role of Pituitary Estrogen Receptors ERα and ERβ on Progesterone Receptor Expression and Action and on Gonadotropin and Prolactin Secretion in the Rat

2004 ◽  
Vol 79 (5) ◽  
pp. 247-258 ◽  
Author(s):  
José E. Sánchez-Criado ◽  
Juana Martín de las Mulas ◽  
Carmina Bellido ◽  
Manuel Tena-Sempere ◽  
Rafaela Aguilar ◽  
...  
Keyword(s):  
Progesterone Receptor ◽  
Estrogen Receptors ◽  
Prolactin Secretion ◽  
Receptor Expression ◽  
Biological Role ◽  
Progesterone Receptor Expression

scholarly journals Interaction between substance P and TRH in the control of prolactin release

2000 ◽  
Vol 166 (2) ◽  
pp. 373-380 ◽  
Author(s):  
BH Duvilanski ◽  
D Pisera ◽  
A Seilicovich ◽  
M del Carmen Diaz ◽  
M Lasaga ◽  
...  
Keyword(s):  
Substance P ◽  
Anterior Pituitary ◽  
Prolactin Secretion ◽  
Male Rat ◽  
Prolactin Release ◽  
Anterior Pituitary Function ◽  
Specific Antagonist ◽  
Autocrine Factor

Substance P (SP) may participate as a paracrine and/or autocrine factor in the regulation of anterior pituitary function. This project studied the effect of TRH on SP content and release from anterior pituitary and the role of SP in TRH-induced prolactin release. TRH (10(-7) M), but not vasoactive intestinal polypeptide (VIP), increased immunoreactive-SP (ir-SP) content and release from male rat anterior pituitary in vitro. An anti-prolactin serum also increased ir-SP release and content. In order to determine whether intrapituitary SP participates in TRH-induced prolactin release, anterior pituitaries were incubated with TRH (10(-7) M) and either WIN 62,577, a specific antagonist of the NK1 receptor, or a specific anti-SP serum. Both WIN 62,577 (10(-8) and 10(-7) M) and the anti-SP serum (1:250) blocked TRH-induced prolactin release. In order to study the interaction between TRH and SP on prolactin release, anterior pituitaries were incubated with either TRH (10(-7) M) or SP, or with both peptides. SP (10(-7) and 10(-6) M) by itself stimulated prolactin release. While 10(-7) M SP did not modify the TRH effect, 10(-6) M SP reduced TRH-stimulated prolactin release. SP (10(-5) M) alone failed to stimulate prolactin release and markedly decreased TRH-induced prolactin release. The present study shows that TRH stimulates ir-SP release and increases ir-SP content in the anterior pituitary. Our data also suggest that SP may act as a modulator of TRH effect on prolactin secretion by a paracrine mechanism.

scholarly journals Membrane Melatonin Receptors Activated Cell Signaling in Physiology and Disease

2021 ◽  
Vol 23 (1) ◽  
pp. 471
Author(s):  
Georgi Nikolaev ◽  
Ralitsa Robeva ◽  
Rossitza Konakchieva
Keyword(s):  
Cell Signaling ◽  
Current Knowledge ◽  
Receptor Activation ◽  
Melatonin Receptors ◽  
Melatonin Receptor ◽  
Functional Relevance ◽  
The Individual ◽  
G Protein Coupled

The pineal hormone melatonin has attracted great scientific interest since its discovery in 1958. Despite the enormous number of basic and clinical studies the exact role of melatonin in respect to human physiology remains elusive. In humans, two high-affinity receptors for melatonin, MT1 and MT2, belonging to the family of G protein-coupled receptors (GPCRs) have been cloned and identified. The two receptor types activate Gi proteins and MT2 couples additionally to Gq proteins to modulate intracellular events. The individual effects of MT1 and MT2 receptor activation in a variety of cells are complemented by their ability to form homo- and heterodimers, the functional relevance of which is yet to be confirmed. Recently, several melatonin receptor genetic polymorphisms were discovered and implicated in pathology—for instance in type 2 diabetes, autoimmune disease, and cancer. The circadian patterns of melatonin secretion, its pleiotropic effects depending on cell type and condition, and the already demonstrated cross-talks of melatonin receptors with other signal transduction pathways further contribute to the perplexity of research on the role of the pineal hormone in humans. In this review we try to summarize the current knowledge on the membrane melatonin receptor activated cell signaling in physiology and pathology and their relevance to certain disease conditions including cancer.

scholarly journals Melatonin activity and receptor expression in endometrial tissue and endometriosis

2019 ◽  
Vol 34 (7) ◽  
pp. 1215-1224 ◽  
Author(s):  
A A Mosher ◽  
M W Tsoulis ◽  
J Lim ◽  
C Tan ◽  
S K Agarwal ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Epithelial Cell ◽  
Endometrial Tissue ◽  
Receptor Expression ◽  
Melatonin Receptors ◽  
Epithelial Cell Proliferation ◽  
Melatonin Receptor ◽  
Eutopic Endometrium ◽  
Endometrial Epithelial Cell ◽  
Research Grant

AbstractSTUDY QUESTIONAre melatonin receptors (melatonin receptor 1A (MR1A) and melatonin receptor 1B (MR1B)) expressed in human endometrium and endometriotic tissue, and does melatonin affect endometrial cell proliferation?SUMMARY ANSWERMelatonin receptors are expressed in human eutopic endometrium, endometriomas and peritoneal lesions, although to different extents, and melatonin treatment attenuated estradiol-induced endometrial epithelial cell proliferation in culture.WHAT IS KNOWN ALREADYMelatonin decreased endometriotic lesion volume in a rat model of endometriosis. Melatonin treatment reduced pain scores in and analgesic use by women with endometriosis.STUDY DESIGN, SIZE, DURATIONBasic science study using human endometrial tissue and an endometrial epithelial cell line.PARTICIPANTS/MATERIALS, SETTING, METHODSMeasurement of melatonin receptor expression (mRNA and protein) in women with surgically confirmed endometriosis (endometrioma (n = 20) or peritoneal lesion (n = 11) alone) and women without surgical evidence of endometriosis (control, n = 15). Collection of endometrial and endometriotic tissue samples, gynecologic history and demographic information. Quantification of estradiol (1.0 nM) and melatonin (0.1 nM–1.0 μM) ± estradiol-induced endometrial epithelial cell proliferation in cultures of endometrial epithelial cells (CRL-1671) following 24 and 48 hours of culture.MAIN RESULTS AND THE ROLE OF CHANCEMR1A and MR1B were localized by immunohistochemistry in glandular epithelial cells of endometrial biopsies from women with and without endometriosis. Both receptors were expressed in eutopic and ectopic endometrial tissue. mRNA expression of MR1A and MR1B was significantly greater in peritoneal lesions than in either endometriomas or eutopic endometrium. However, protein expression of MR1A was decreased in peritoneal lesions compared to control eutopic endometrium, whereas MR1B expression did not differ between the groups. Melatonin (0.1 nM–1.0 μM) treatment inhibited estradiol (1.0 nM)-induced endometrial epithelial cell proliferation at 48 hours but not 24 hours of culture.LIMITATIONS, REASONS FOR CAUTIONBeneficial effects of melatonin seen in culture have yet to be comprehensively evaluated in women with endometriosis.WIDER IMPLICATIONS OF THE FINDINGSOur data suggest that melatonin may be useful as an adjunct to current endometriosis treatments.STUDY FUNDING/COMPETING INTEREST(S)This study was supported by the Canadian Institutes of Health Research (grant MOP142230 to W.G.F.). A.A.M. is supported by a resident research grant through the Physicians Services Incorporated Foundation. The authors have no conflicts of interest.

Anterior pituitary hormone secretion in chronic schizophrenia – an approach to neurohumoral mechanisms

1977 ◽  
Vol 7 (2) ◽  
pp. 223-228 ◽  
Author(s):  
Eve C. Johnstone ◽  
T. J. Crow ◽  
K. Mashiter
Keyword(s):  
Anterior Pituitary ◽  
Hormone Secretion ◽  
Chronic Schizophrenia ◽  
Mental States ◽  
Prolactin Secretion ◽  
Pituitary Hormone ◽  
Anterior Pituitary Hormone ◽  
Anterior Pituitary Function ◽  
Male Patients

SynopsisProlactin, FSH, LH and TSH were determined in repeated samples of serum from 16 unmedicated male patients with chronic schizophrenia. Changes in the mental states between the 2 occasions were related to changes in hormone levels. Significant inverse correlations were established between prolactin and incoherence of speech, between prolactin and total positive symptoms and between FSH and poverty of speech. A significant positive correlation was established between FSH and delusions. These findings are discussed in the context of evidence concerning the role of monoamines in the control of anterior pituitary function, and of the dopamine and other monoamine hypotheses of schizophrenia. Although prolactin secretion was not as low, as would be predicted on the basis of the dopamine overactivity hypothesis of schizophrenia, the relationship between symptom change and change in prolactin secretion was consistent with the hypothesis that increasing symptom severity is associated with increasing dopamine release from the tubero-infundibular system.

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