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Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, University of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, 7 Donghu South Road, Wuhan, Hubei 430072, People's Republic of China
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Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, University of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, 7 Donghu South Road, Wuhan, Hubei 430072, People's Republic of China
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Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, University of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, 7 Donghu South Road, Wuhan, Hubei 430072, People's Republic of China
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mammalian endocrine signals are still unclear. Our data indicated that the levels of gnrhr2 , lhb , and gonadal steroid receptors, such as ar , pgr , er1 , and er2b , were significantly higher in the pituitary gland of adult zebrafish ( Table 4
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The recent demonstration that the mammary gland of the dog secretes growth hormone (GH) in response to endogenous or exogenous progestins, and may secrete it in amounts sufficient to cause acromegaly (Selman et al. 1994), highlights the concept that the mammary gland should be viewed as an endocrine organ and not simply as an exocrine gland receiving but not sending hormonal signals. Interest in the mammary gland as a source of hormones is not new; indeed, in the years up to the Second World War mammary extracts were included in pharmacopoeias for the treatment of uterine congestion, fibroids, menorrhagia and even morning sickness in pregnancy. However, it is difficult to judge the significance of early experiments since the results were not tightly controlled nor subjected to statistical analysis. Attempts to replicate some of the apparently more interesting effects of mammary extract have failed (M Peaker & E Taylor, unpublished observations).
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One of the fundamental questions in endocrinology is how circulating or locally produced hormones affect target cell functions by activating specific receptors linked to numerous signal-transduction pathways. An important subset of G protein-coupled cell-surface receptors can activate phospholipase C enzymes to hydrolyze a small but critically important class of phospholipids, the phosphoinositides. Although this signaling pathway has been extensively explored over the last 20 years, this has proven to be only the tip of the iceberg, and the multiplicity and diversity of the cellular functions controlled by phosphoinositides have surpassed any imagination. Phosphoinositides have been found to be key regulators of ion channels and transporters, and controllers of vesicular trafficking and the transport of lipids between intracellular membranes. Essentially, they organize the recruitment and regulation of signaling protein complexes in specific membrane compartments. While many of these processes have been classically studied by cell biologists, molecular endocrinology cannot ignore these recent advances, and now needs to integrate the cell biologist’s views in the modern concept of how hormones affect cell functions and how derailment of simple molecular events can lead to complex endocrine and metabolic disorders.
ZBSA – Freiburg Center for Systems Biology, University of Freiburg, Germany
Renal Division, University Hospital Freiburg, Germany
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ZBSA – Freiburg Center for Systems Biology, University of Freiburg, Germany
Renal Division, University Hospital Freiburg, Germany
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ZBSA – Freiburg Center for Systems Biology, University of Freiburg, Germany
Renal Division, University Hospital Freiburg, Germany
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Modulation of insulin/IGF signaling in the nematode Caenorhabditis elegans is the central determinant of the endocrine control of stress response, diapause, and aging. Mutations in many genes that interfere with, or are controlled by, insulin signaling have been identified in the last decade by genetic analyses in the worm. Most of these genes have orthologs in vertebrate genomes, and their functional characterization has provided multiple hints about conserved mechanisms for the genetic influence on aging. The emerging picture is that insulin-like molecules, through the activity of the DAF-2/insulin/ IGF-I-like receptor, and the DAF-16/FKHRL1/FOXO transcription factor, control the ability of the organism to deal with oxidative stress, and interfere with metabolic programs that help to determine lifespan.
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Endocrine Signalling Group, Barts and the London School of Medicine and Dentistry, Department of Medicine, Cardiovascular and Inflammation Group, Laboratory for Integrated Neurosciences and Endocrinology, Veterinary Basic Sciences, Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK
Endocrine Signalling Group, Barts and the London School of Medicine and Dentistry, Department of Medicine, Cardiovascular and Inflammation Group, Laboratory for Integrated Neurosciences and Endocrinology, Veterinary Basic Sciences, Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK
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In the pituitary, C-type natriuretic peptide (CNP) has been implicated as a gonadotroph-specific factor, yet expression of the CNP gene (Nppc) and CNP activity in gonadotrophs is poorly defined. Here, we examine the molecular expression and putative function of a local gonadotroph natriuretic peptide system. Nppc, along with all three natriuretic peptide receptors (Npr1, Npr2 and Npr3), was expressed in both αT3-1 and LβT2 cells and primary mouse pituitary tissue, yet the genes for atrial-(ANP) and B-type natriuretic peptides (Nppa and Nppb) were much less abundant. Putative processing enzymes of CNP were also expressed in αT3-1 cells and primary mouse pituitaries. Transcriptional analyses revealed that the proximal 50 bp of the murine Nppc promoter were sufficient for GNRH responsiveness, in an apparent protein kinase C and calcium-dependent manner. Electrophoretic mobility shift assays showed Sp1/Sp3 proteins form major complexes within this region of the Nppc promoter. CNP protein was detectable in rat anterior pituitaries, and electron microscopy detected CNP immunoreactivity in secretory granules of gonadotroph cells. Pharmacological analyses of natriuretic peptide receptor activity clearly showed ANP and CNP are potent activators of cGMP production. However, functional studies failed to reveal a role for CNP in regulating cell proliferation or LH secretion. Surprisingly, CNP potently stimulated the human glycoprotein hormone α-subunit promoter in LβT2 cells but not in αT3-1 cells. Collectively, these findings support a role for CNP as the major natriuretic peptide of the anterior pituitary, and for gonadotroph cells as the major source of CNP expression and site of action.
Division of Clinical Developmental Sciences, Academic Section of Obstetrics and Gynaecology, Centre for Developmental and Endocrine Signalling, St George’s University of London, Cranmer Terrace, London SW17 0RE, UK
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Division of Clinical Developmental Sciences, Academic Section of Obstetrics and Gynaecology, Centre for Developmental and Endocrine Signalling, St George’s University of London, Cranmer Terrace, London SW17 0RE, UK
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Division of Clinical Developmental Sciences, Academic Section of Obstetrics and Gynaecology, Centre for Developmental and Endocrine Signalling, St George’s University of London, Cranmer Terrace, London SW17 0RE, UK
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Cortisol–cortisone metabolism is catalysed by the bi-directional NADP(H)-dependent type 1 11β-hydroxysteroid dehydrogenase (11βHSD1) enzyme and the oxidative NAD+-dependent type 2 11βHSD (11βHSD2). This study related the expression of 11βHSD1 and 11βHSD2 enzymes (mRNA and protein) to net 11-ketosteroid reductase and 11β-dehydrogenase (11β-DH) activities in bovine follicular granulosa and luteal cells. Granulosa cells were isolated from follicles of < 4, 4–8, > 8 and > 12 mm in diameter in either the follicular or luteal phase of the ovarian cycle. Luteal cells were obtained from corpora lutea (CL) in the early non-pregnant luteal phase. Enzyme expression was assessed by reverse transcription-PCR and western blotting, while enzyme activities were measured over 1 h in cell homogenates using radiometric conversion assays with 100 nM [3H]cortisone or [3H]cortisol and pyridine dinucleotide cofactors. Irrespective of follicle diameter, the expression of 11βHSD2 and NAD+-dependent oxidation of cortisol predominated in granulosa cells harvested in the follicular phase. In contrast, in granulosa cells obtained from luteal phase follicles and in bovine luteal cells, expression of 11βHSD1 exceeded that of 11βHSD2 and the major enzyme activity was NADP+-dependent cortisol oxidation. Increasing follicular diameter was associated with progressive increases in expression and activities of 11βHSD2 and 11βHSD1 in follicular and luteal phase granulosa cells respectively. In follicular phase granulosa cells from antral follicles < 12 mm, 11βHSD1 migrated with a molecular mass of 34 kDa, whereas in the dominant follicle, CL and all luteal phase granulosa cells, a second protein band of 68 kDa was consistently detected. In all samples, 11βHSD2 had a molecular mass of 48 kDa, but in large antral follicles (> 8 mm), there was an additional immunoreactive band at 50 kDa. We conclude that 11βHSD2 is the predominant functional 11βHSD enzyme expressed in follicular phase granulosa cells from growing bovine antral follicles. In contrast, in bovine granulosa cells from dominant or luteal phase follicles, and in bovine luteal cells from early non-pregnant CL, 11βHSD1 is the major glucocorticoid-metabolising enzyme. The increasing levels of cortisol inactivation by the combined NADP+- and NAD+-dependent 11β-DH activities suggest a need to restrict cortisol access to corticosteroid receptors in the final stages of follicle development.
Department of Veterinary Basic Science, Royal Veterinary College, Royal College Street, London NW1 0TU, UK
Department of Clinical Science at South Bristol (Obstetrics and Gynaecology), University of Bristol, Dorothy Hodgkin Building, Whitson Street, Bristol BS1 3NY, UK
Division of Clinical Developmental Sciences, Academic Section of Obstetrics and Gynaecology, Centre for Developmental and Endocrine Signalling, St George’s University of London, Cranmer Terrace, Tooting, London SW17 0RE UK
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Department of Veterinary Basic Science, Royal Veterinary College, Royal College Street, London NW1 0TU, UK
Department of Clinical Science at South Bristol (Obstetrics and Gynaecology), University of Bristol, Dorothy Hodgkin Building, Whitson Street, Bristol BS1 3NY, UK
Division of Clinical Developmental Sciences, Academic Section of Obstetrics and Gynaecology, Centre for Developmental and Endocrine Signalling, St George’s University of London, Cranmer Terrace, Tooting, London SW17 0RE UK
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Department of Veterinary Basic Science, Royal Veterinary College, Royal College Street, London NW1 0TU, UK
Department of Clinical Science at South Bristol (Obstetrics and Gynaecology), University of Bristol, Dorothy Hodgkin Building, Whitson Street, Bristol BS1 3NY, UK
Division of Clinical Developmental Sciences, Academic Section of Obstetrics and Gynaecology, Centre for Developmental and Endocrine Signalling, St George’s University of London, Cranmer Terrace, Tooting, London SW17 0RE UK
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Department of Veterinary Basic Science, Royal Veterinary College, Royal College Street, London NW1 0TU, UK
Department of Clinical Science at South Bristol (Obstetrics and Gynaecology), University of Bristol, Dorothy Hodgkin Building, Whitson Street, Bristol BS1 3NY, UK
Division of Clinical Developmental Sciences, Academic Section of Obstetrics and Gynaecology, Centre for Developmental and Endocrine Signalling, St George’s University of London, Cranmer Terrace, Tooting, London SW17 0RE UK
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Department of Veterinary Basic Science, Royal Veterinary College, Royal College Street, London NW1 0TU, UK
Department of Clinical Science at South Bristol (Obstetrics and Gynaecology), University of Bristol, Dorothy Hodgkin Building, Whitson Street, Bristol BS1 3NY, UK
Division of Clinical Developmental Sciences, Academic Section of Obstetrics and Gynaecology, Centre for Developmental and Endocrine Signalling, St George’s University of London, Cranmer Terrace, Tooting, London SW17 0RE UK
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In luteinizing granulosa cells, prostaglandin E2 (PGE2) can exert luteotrophic actions, apparently via the cAMP signalling pathway. In addition to stimulating progesterone synthesis, PGE2 can also stimulate oxidation of the physiological glucocorticoid, cortisol, to its inactive metabolite, cortisone, by the type 1 11β-hydroxysteroid dehydrogenase (11βHSD1) enzyme in human granulosa–lutein cells. Having previously shown these human ovarian cells to express functional G-protein coupled, E-series prostaglandin (PTGER)1, PTGER2 and PTGER4 receptors, the aim of this study was to delineate the roles of PTGER1 and PTGER2 receptors in mediating the effects of PGE2 on steroidogenesis and cortisol metabolism in human granulosa–lutein cells. PGE2-stimulated concentration-dependent increases in both progesterone production and cAMP accumulation (by 1.9 ± 0.1- and 18.7 ± 6.8-fold respectively at 3000 nM PGE2). While a selective PTGER1 antagonist, SC19220, could partially inhibit the steroidogenic response to PGE2 (by 55.9 ± 4.1% at 1000 nM PGE2), co-treatment with AH6809, a mixed PTGER1/PTGER2 receptor antagonist, completely abolished the stimulation of progesterone synthesis at all tested concentrations of PGE2 and suppressed the stimulation of cAMP accumulation. Both PGE2 and butaprost (a preferential PTGER2 receptor agonist) stimulated concentration-dependent increases in cortisol oxidation by 11βHSD1 (by 42.5 ± 3.1 and 40.0 ± 3.0% respectively, at PGE2 and butaprost concentrations of 1000 nM). Co-treatment with SC19220 enhanced the ability of both PGE2 and butaprost to stimulate 11βHSD1 activity (by 30.2 ± 0.2 and 30.5 ± 0.6% respectively), whereas co-treatment with AH6809 completely abolished the 11βHSD1 responses to PGE2 and butaprost. These findings implicate the PTGER2 receptor–cAMP signalling pathway in the stimulation of progesterone production and 11βHSD1 activity by PGE2 in human granulosa–lutein cells.
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-Moreno et al . 2005 a ). Adequate horn growth in spring has a high energy demand, and it may be that the high levels of testosterone seen in the mating season provide an endocrine signal that stops this growth, thus allowing energy use to be refocused
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BIO5 Institute, University of Arizona, Tucson, Arizona, USA
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nervous system. Introduction Energy and glucose homeostasis are tightly controlled by coordinated neural and endocrine signals that facilitate tissue crosstalk and central nervous system (CNS) integration to regulate food intake, energy expenditure
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, advancing the concept that the liver is an important mediator of these processes. Specifically, the liver integrates endocrine signals from the SST-GH-testosterone, HPT, and HPA axes to modulate the expression of the major plasma binding proteins for thyroid
