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Jeng SR, Wu GC, Yueh WS, Liu PH, Kuo SF, Dufour S, Chang CF. The expression profiles of cyp19a1, sf-1, esrs and gths in the brain-pituitary during gonadal sex differentiation in juvenile Japanese eels. Gen Comp Endocrinol 2024; 353:114512. [PMID: 38582176 DOI: 10.1016/j.ygcen.2024.114512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 03/08/2024] [Accepted: 04/03/2024] [Indexed: 04/08/2024]
Abstract
Eels are gonochoristic species whose gonadal differentiation initiates at the yellow eel stage and is influenced by environmental factors. We revealed some sex-related genes were sex dimorphically expressed in gonads during gonadal sex differentiation of Japanese eel (Anguilla japonica); however, the expression of sex-related genes in the brain-pituitary during gonadal sex differentiation in eels is still unclear. This study aimed to investigate the sex-related gene expressions in the brain-pituitary and tried to clarify their roles in the brain and gonads during gonadal sex differentiation. Based on our previous histological study, the control eels developed as males, and estradiol-17β (E2) was used for feminization. Our results showed that during testicular differentiation, the brain cyp19a1 transcripts and aromatase proteins were increased significantly; moreover, the cyp19a1, sf-1, foxl2s, and esrs (except gperb) transcripts in the midbrain/pituitary also were increased significantly. Forebrain gnrh1 transcripts increased slightly during gonadal differentiation of both sexes, but the gnrhr1b and gnrhr2 transcripts in the midbrain/pituitary were stable during gonadal differentiation. The expression levels of gths and gh in the midbrain/pituitary were significantly increased during testicular differentiation and were much higher in males than in E2-feminized females. These results implied that endogenous estrogens might play essential roles in the brain/pituitary during testicular differentiation, sf-1, foxl2s, and esrs may have roles in cyp19a1 regulation in the midbrain/pituitary of Japanese eels. For the GnRH-GTH axis, gths, especially fshb, may be regulated by esrs and involved in regulating testicular differentiation and development in Japanese eels.
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Affiliation(s)
- Shan-Ru Jeng
- Department of Aquaculture, National Kaohsiung University of Science and Technology, Kaohsiung 811, Taiwan.
| | - Guan-Chung Wu
- Department of Aquaculture, National Taiwan Ocean University, Keelung 202, Taiwan.
| | - Wen-Shiun Yueh
- Department of Aquaculture, National Kaohsiung University of Science and Technology, Kaohsiung 811, Taiwan
| | - Pei-Hua Liu
- Department of Aquaculture, National Kaohsiung University of Science and Technology, Kaohsiung 811, Taiwan
| | - Shu-Fen Kuo
- Department of Aquaculture, National Kaohsiung University of Science and Technology, Kaohsiung 811, Taiwan
| | - Sylvie Dufour
- Biology of Aquatic Organisms and Ecosystems (BOREA), Muséum National d'Histoire Naturelle, Sorbonne Université, CNRS, IRD, Paris, France; Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung 202, Taiwan
| | - Ching-Fong Chang
- Department of Aquaculture, National Taiwan Ocean University, Keelung 202, Taiwan; Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung 202, Taiwan.
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Kalarani A, Vinodha V, Moses IR. Inter-relations of brain neurosteroids and monoamines towards reproduction in fish. REPRODUCTION AND BREEDING 2021. [DOI: 10.1016/j.repbre.2021.09.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
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Fontaine R, Royan MR, von Krogh K, Weltzien FA, Baker DM. Direct and Indirect Effects of Sex Steroids on Gonadotrope Cell Plasticity in the Teleost Fish Pituitary. Front Endocrinol (Lausanne) 2020; 11:605068. [PMID: 33365013 PMCID: PMC7750530 DOI: 10.3389/fendo.2020.605068] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 10/12/2020] [Indexed: 12/26/2022] Open
Abstract
The pituitary gland controls many important physiological processes in vertebrates, including growth, homeostasis, and reproduction. As in mammals, the teleost pituitary exhibits a high degree of plasticity. This plasticity permits changes in hormone production and secretion necessary to meet the fluctuating demands over the life of an animal. Pituitary plasticity is achieved at both cellular and population levels. At the cellular level, hormone synthesis and release can be regulated via changes in cell composition to modulate both sensitivity and response to different signals. At the cell population level, the number of cells producing a given hormone can change due to proliferation, differentiation of progenitor cells, or transdifferentiation of specific cell types. Gonadotropes, which play an important role in the control of reproduction, have been intensively investigated during the last decades and found to display plasticity. To ensure appropriate endocrine function, gonadotropes rely on external and internal signals integrated at the brain level or by the gonadotropes themselves. One important group of internal signals is the sex steroids, produced mainly by the gonadal steroidogenic cells. Sex steroids have been shown to exert complex effects on the teleost pituitary, with differential effects depending on the species investigated, physiological status or sex of the animal, and dose or method of administration. This review summarizes current knowledge of the effects of sex steroids (androgens and estrogens) on gonadotrope cell plasticity in teleost anterior pituitary, discriminating direct from indirect effects.
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Affiliation(s)
- Romain Fontaine
- Physiology Unit, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Muhammad Rahmad Royan
- Physiology Unit, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Kristine von Krogh
- Physiology Unit, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Finn-Arne Weltzien
- Physiology Unit, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Dianne M. Baker
- Department of Biological Sciences, University of Mary Washington, Fredericksburg, VA, United States
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Jiang Q, Zhang Q, Lian A, Xu Y. Irisin stimulates gonadotropins gene expression in tilapia (Oreochromis niloticus) pituitary cells. Anim Reprod Sci 2017; 185:140-147. [DOI: 10.1016/j.anireprosci.2017.06.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 06/18/2017] [Accepted: 06/26/2017] [Indexed: 12/18/2022]
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Trubiroha A, Kroupova H, Wuertz S, Kloas W. Up-regulation of gonadotropin mRNA-expression at the onset of gametogenesis in the roach (Rutilus rutilus): evidence for an important role of brain-type aromatase (cyp19a1b) in the pituitary. Gen Comp Endocrinol 2012; 178:529-38. [PMID: 22814335 DOI: 10.1016/j.ygcen.2012.07.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Revised: 07/04/2012] [Accepted: 07/06/2012] [Indexed: 01/12/2023]
Abstract
The present study characterized changes in key parameters of reproduction in adult roach (Rutilus rutilus) from Lake Grosser Mueggelsee (Berlin, Germany) during natural gametogenesis. Fish of both sexes were sampled in monthly intervals between April and August in order to cover the onset of gametogenesis. Investigated parameters included gonad histology, plasma levels of 17β-oestradiol (E2), testosterone (T), 11-ketotestosterone (11-KT), and 17,20β-dihydroxy-4-pregnen-3-one (17,20β-P) as well as the expression of gonadotropin subunits in the pituitary. Furthermore, the mRNA-expression of brain-type aromatase (cyp19a1b), androgen receptor (ar), and estrogen receptor isoforms was studied at the pituitary level. The onset of gametogenesis - as indicated by follicles with cortical alveoli in females and first spermatogonia B in males - was observed in July, accompanied by a significant up-regulation of follicle-stimulating hormone β (fshβ) mRNA in the pituitary in both sexes. On the other hand, luteinizing hormone β (lhβ) mRNA increased later on in August. In males, the increase of fshβ mRNA in July coincided with a rise in plasma 11-KT concentrations. In females, E2 in plasma increased later, not until August, shortly before true vitellogenesis (late cortical alveoli stage). Expression of sex steroid receptors in the pituitary revealed only minor seasonal fluctuations. Most pronounced, ar mRNA displayed the highest level pre-spawning in both sexes. Interestingly, cyp19a1b mRNA-expression in the pituitary increased in parallel with fshβ already before any changes in plasma E2 or T occurred. These data suggest an important role of pituitary FSH and aromatase at the onset of gametogenesis in the roach.
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Affiliation(s)
- Achim Trubiroha
- Department of Ecophysiology and Aquaculture, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Mueggelseedamm 310, D-12587 Berlin, Germany.
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Jeng SR, Yueh WS, Pen YT, Gueguen MM, Pasquier J, Dufour S, Chang CF, Kah O. Expression of aromatase in radial glial cells in the brain of the Japanese eel provides insight into the evolution of the cyp191a gene in Actinopterygians. PLoS One 2012; 7:e44750. [PMID: 22957105 PMCID: PMC3434150 DOI: 10.1371/journal.pone.0044750] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 08/06/2012] [Indexed: 11/23/2022] Open
Abstract
The cyp19a1 gene that encodes aromatase, the only enzyme permitting conversion of C19 aromatizable androgens into estrogens, is present as a single copy in the genome of most vertebrate species, except in teleosts in which it has been duplicated. This study aimed at investigating the brain expression of a cyp19a1 gene expressed in both gonad and brain of Japanese eel, a basal teleost. By means of immunohistochemistry and in situ hybridization, we show that cyp19a1 is expressed only in radial glial cells of the brain and in pituitary cells. Treatments with salmon pituitary homogenates (female) or human chorionic gonadotrophin (male), known to turn on steroid production in immature eels, strongly stimulated cyp19a1 messenger and protein expression in radial glial cells and pituitary cells. Using double staining studies, we also showed that aromatase-expressing radial glial cells exhibit proliferative activity in both the brain and the pituitary. Altogether, these data indicate that brain and pituitary expression of Japanese eel cyp19a1 exhibits characteristics similar to those reported for the brain specific cyp19a1b gene in teleosts having duplicated cyp19a1 genes. This supports the hypothesis that, despite the fact that eels also underwent the teleost specific genome duplication, they have a single cyp19a1 expressed in both brain and gonad. Such data also suggest that the intriguing features of brain aromatase expression in teleost fishes were not gained after the whole genome duplication and may reflect properties of the cyp19a1 gene of ancestral Actinopterygians.
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Affiliation(s)
- Shan-Ru Jeng
- Department of Aquaculture, National Kaohsiung Marine University, Kaohsiung, Taiwan
- Team NEED, Institut de Recherche en Santé, Environnement et Travail, INSERM U1085, IFR140, Université de Rennes 1, Rennes, France
| | - Wen-Shiun Yueh
- Department of Aquaculture, National Kaohsiung Marine University, Kaohsiung, Taiwan
| | - Yi-Ting Pen
- Department of Aquaculture, National Kaohsiung Marine University, Kaohsiung, Taiwan
| | - Marie-Madeleine Gueguen
- Team NEED, Institut de Recherche en Santé, Environnement et Travail, INSERM U1085, IFR140, Université de Rennes 1, Rennes, France
| | - Jérémy Pasquier
- Research Unit BOREA, Biology of Aquatic Organisms and Ecosystems, CNRS 7208/IRD 207/UPMC, Muséum National d'Histoire Naturelle, Paris, France
| | - Sylvie Dufour
- Research Unit BOREA, Biology of Aquatic Organisms and Ecosystems, CNRS 7208/IRD 207/UPMC, Muséum National d'Histoire Naturelle, Paris, France
| | - Ching-Fong Chang
- Research Unit BOREA, Biology of Aquatic Organisms and Ecosystems, CNRS 7208/IRD 207/UPMC, Muséum National d'Histoire Naturelle, Paris, France
- Department of Aquaculture, Center of Excellence for Marine Bioenvironment and Biotechnology, National Taiwan Ocean University, Keelung, Taiwan
| | - Olivier Kah
- Team NEED, Institut de Recherche en Santé, Environnement et Travail, INSERM U1085, IFR140, Université de Rennes 1, Rennes, France
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Do Rego JL, Seong JY, Burel D, Leprince J, Luu-The V, Tsutsui K, Tonon MC, Pelletier G, Vaudry H. Neurosteroid biosynthesis: enzymatic pathways and neuroendocrine regulation by neurotransmitters and neuropeptides. Front Neuroendocrinol 2009; 30:259-301. [PMID: 19505496 DOI: 10.1016/j.yfrne.2009.05.006] [Citation(s) in RCA: 282] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2009] [Revised: 05/12/2009] [Accepted: 05/21/2009] [Indexed: 01/09/2023]
Abstract
Neuroactive steroids synthesized in neuronal tissue, referred to as neurosteroids, are implicated in proliferation, differentiation, activity and survival of nerve cells. Neurosteroids are also involved in the control of a number of behavioral, neuroendocrine and metabolic processes such as regulation of food intake, locomotor activity, sexual activity, aggressiveness, anxiety, depression, body temperature and blood pressure. In this article, we summarize the current knowledge regarding the existence, neuroanatomical distribution and biological activity of the enzymes responsible for the biosynthesis of neurosteroids in the brain of vertebrates, and we review the neuronal mechanisms that control the activity of these enzymes. The observation that the activity of key steroidogenic enzymes is finely tuned by various neurotransmitters and neuropeptides strongly suggests that some of the central effects of these neuromodulators may be mediated via the regulation of neurosteroid production.
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Affiliation(s)
- Jean Luc Do Rego
- Institut National de la Santé et de la Recherche Médicale (INSERM) Unité 413, 76821 Mont-Saint-Aignan, France
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Kitahashi T, Ogawa S, Soga T, Sakuma Y, Parhar I. Sexual maturation modulates expression of nuclear receptor types in laser-captured single cells of the cichlid (Oreochromis niloticus) pituitary. Endocrinology 2007; 148:5822-30. [PMID: 17823257 DOI: 10.1210/en.2007-0311] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The role of steroid/thyroid hormones in the regulation of endocrine cells at the level of the pituitary has remained unclear. Therefore, using single-cell quantitative real-time PCR, we examined absolute amounts of transcripts for nuclear receptors [estrogen receptors (ERs) alpha, beta, and gamma; androgen receptors (ARs) a and b; glucocorticoid receptors (GRs) 1, 2a, and 2b; and thyroid hormone receptors (TRs) alpha1, alpha2, and beta] in pituitary cells of immature (IM) and mature (M) male tilapia, Oreochromis niloticus. In the two reproductive stages, ACTH cells expressed only ERbeta, whereas all other pituitary cell types expressed ERalpha + beta, and a subpopulation coexpressed ARa, ARb, GR1, GR2b, and TRbeta but lacked ERgamma, GR2a, TRalpha1, and TRalpha2. IM males had high percentages of LH cells (IM 46.0% vs. M 10.0%), GH cells (IM 23.3% vs. M 7.9%), and prolactin cells (IM 68.8% vs. M 6.0%) with ERbeta, and TSH cells (IM 19.2% vs. M 0.0%) and MSH cells (IM 25.6% vs. M 0.0%) with ERalpha + TRbeta. A high percentage of FSH cells in IM males expressed ERbeta (IM 46.9% vs. M 18.8%), and FSH cells in M males showed significantly high GR1 transcripts (IM 76.0 +/- 5.0 vs. M 195.0 +/- 10.7 copies per cell; P < 0.05), suggesting that FSH cells are regulated differently in the two reproductive stages. Coexpression of ERalpha + beta in high percentages of cells of the GH family (GH, IM 43.8% vs. M 14.3%; prolactin, IM 8.3% vs. M 59.7%; somatolactin, IM 22.2% vs. M 42.2%) suggests that the expression of both ERs is important for functionality. Thus, differential coexpression of genes for nuclear receptors in subpopulations of pituitary cell types suggests multiple steroid/thyroid hormone regulatory pathways at the level of the pituitary during the two reproductive stages.
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Affiliation(s)
- Takashi Kitahashi
- School of Medicine and Health Sciences, Monash University, 46150 Bandar Sunway, Selangor, Malaysia
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van Nes S, Moe M, Andersen Ø. Molecular characterization and expression of twocyp19 (P450 aromatase) genes in embryos, larvae, and adults of Atlantic halibut (Hippoglossus hippoglossus). Mol Reprod Dev 2005; 72:437-49. [DOI: 10.1002/mrd.20373] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Piferrer F, Blázquez M. Aromatase distribution and regulation in fish. FISH PHYSIOLOGY AND BIOCHEMISTRY 2005; 31:215-226. [PMID: 20035461 DOI: 10.1007/s10695-006-0027-0] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Cytochrome P450 aromatase is the enzyme complex responsible for the synthesis of estrogens by the aromatization of androgens. In the vast majority of tetrapods examined so far, aromatase is the product of the Cyp19 gene, which exists as a single copy per haploid genome. In contrast, in teleosts there are two isoforms of the aromatase gene, Cyp19a and Cyp19b, which encode two structurally different proteins, P450aromA and P450aromB, respectively, with similar catalytic activities. The promoter region of both genes has been characterized in several teleost species and more than 20 different regulatory sites have been identified to date. These include response elements for members of the nuclear receptor superfamily, notably sex steroid receptors, and at least five transcription factors related to neurogenesis. This supports the idea that, besides other functions such as the control of reproduction, aromatase and therefore estrogens are actively involved in neurogenesis. Aromatase mRNA expression studies revealed that P450aromA and P450aromB are preferentially, but not exclusively, expressed in the gonads and brain, respectively. Other organs and tissues where aromatase is expressed, albeit at much lower levels include the pituitary, retina, anterior kidney, testis, liver and visceral fat, suggesting local actions of estrogens in several peripheral targets. Gene expression levels are usually matched by actual catalytic activity, with K (m) usually in the range 5-50 nM and V (max) in the order of a few pmol/mg protein/h. The current challenge is to understand the regulation of both aromatase genes, especially in the context of sex differentiation and as a response to environmental factors, including temperature, social interactions, and endocrine disruptors, which is briefly reviewed. It is also important to gain a better understanding of the specific functions of estrogen in different tissues and key developmental and reproductive events throughout the fish life.
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Affiliation(s)
- Francesc Piferrer
- Institut de Ciències del Mar, Consejo Superior de Investigaciones Científicas (CSIC), Passeig Marítim, 37-49, 08003, Barcelona, Spain,
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Goto-Kazeto R, Kight KE, Zohar Y, Place AR, Trant JM. Localization and expression of aromatase mRNA in adult zebrafish. Gen Comp Endocrinol 2004; 139:72-84. [PMID: 15474538 DOI: 10.1016/j.ygcen.2004.07.003] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2004] [Revised: 06/15/2004] [Accepted: 07/06/2004] [Indexed: 11/21/2022]
Abstract
Estradiol plays a key role in the control of many behavioral and physiological aspects of reproduction therefore the expression of cytochrome P450 aromatase (CYP19), the enzyme responsible for the conversion of androgens to estrogens, is of vital interest. The zebrafish, and many other teleosts, have two aromatase genes (CYP19A1 and CYP19A2) that are expressed predominantly in the ovary and brain, respectively, however, the physiological impact of extra-gonadal aromatase has been poorly described. In this study, in situ hybridizations of whole-mount and paraffin sections of adult zebrafish brains, pituitaries, and ovarian follicles showed that CYP19A2 was strongly expressed in the olfactory bulb (OB), ventral telencephalon (TEL), preoptic area (POA), and ventral/caudal hypothalamic zone (HT) of the brain, and in the anterior and posterior lobes of the pituitary. The regional distribution of the CYP19A2 mRNA did not vary with sex however transcript abundance varied within (male "high expressers" had much higher expression in the OB, TEL, and HT than in "low expressers") and between sexes (higher in OB, TEL, and HT of males than in females). In situ hybridizations of CYP19A1 failed to develop a signal in the brain or pituitary but were detectable by RT-PCR. CYP19A1 was highly expressed in Stage III B follicles (>500 nm) with significantly lower levels in the Stage IV follicles (>680 nm), Stage III A follicles (>350 nm), and Stage I and II follicles (350 microm) which were embedded in connective tissues. The differential expression of the aromatase genes, particularly CYP19A2 in the brain, suggests that the two aromatase genes play different roles in the reproductive behavior and/or physiology of bony fish.
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Affiliation(s)
- Rie Goto-Kazeto
- Center of Marine Biotechnology, University of Maryland Biotechnology Institute, Baltimore 21202, USA
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Evrard HC, Harada N, Balthazart J. Immunocytochemical localization of aromatase in sensory and integrating nuclei of the hindbrain in Japanese quail (Coturnix japonica). J Comp Neurol 2004; 473:194-212. [PMID: 15101089 DOI: 10.1002/cne.20068] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The distribution of the estrogen synthesizing enzyme (aromatase) in the hindbrain (rhombencephalon and mesencephalon) of male adult quail was investigated by immunocytochemistry. Aromatase-immunoreactive neuronal structures (perikarya and fibers bearing punctate structures) were observed in sensory (trigeminal, solitary tract, vestibular, optic tectum) and integrating (parabrachial, periaqueductal, cerulean, raphe) nuclei. Besides the expression of aromatase in these well-delineated nuclei, dense to scattered networks of immunoreactive fibers were found dispersed throughout the hindbrain and, in particular, in its rostral and dorsal parts. To a lesser extent, they were also present throughout the premotor nuclei of the reticular formation and in various fiber tracts. In contrast, no immunoreactive signal was found in motor nuclei, and in most of the statoacoustic (cerebellum, cochlear, olive, pontine, part of vestibular) nuclei. The expression of aromatase in perikarya and fibers in areas of the adult hindbrain where estrogen receptors have been identified previously suggests a role for estrogens locally produced in the regulation of sensory and integrating functions, contrary to the widespread assumption that these functions are regulated exclusively by steroids produced in the gonads.
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Affiliation(s)
- Henry C Evrard
- Center for Cellular and Molecular Neurobiology, Research Group in Behavioral Neuroendocrinology, University of Liège, B-4020 Liège, Belgium.
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González A, Piferrer F. Aromatase activity in the European sea bass (Dicentrarchus labrax L.) brain. Distribution and changes in relation to age, sex, and the annual reproductive cycle. Gen Comp Endocrinol 2003; 132:223-30. [PMID: 12812769 DOI: 10.1016/s0016-6480(03)00086-8] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Cytochrome P450 aromatase activity (AA) was measured in different tissues of the sea bass (Dicentrarchus labrax L.) using a tritiated water release assay that was previously optimized and validated for this species. In adult fish entering the reproductive season, AA was highest on a per mg protein basis, in the brain (2.04+/-0.4 pmol/mg prot/h; mean+/-SEM), followed by the ovary (0.59+/-0.1) and was detectable in visceral fat (0.21+/-0.05), liver (0.08+/-0.009), and head kidney (0.03+/-0.004). However, AA was negligible in the rest of the tissues tested: heart, testis, muscle, and spleen. Consistent with results obtained in other species, dissection of the brain into its major constitutive parts revealed that AA was concentrated in areas implicated in the control of reproduction, including the olfactory bulb, telencephalon, and hypothalamus (range: 2.6-16.2 pmol/mg prot/h), as well as the pituitary gland (6.2-9.3 pmol/mg prot/h). Lower AA was noted in the optic bulb, cerebellum, and medulla. However, in contrast to some previously published reports concerning the content and distribution of neural aromatase in fish, males consistently exhibited higher AA than females. In one-year-old juvenile fish completing the process of gonadal sex differentiation, brain AA (0.63 pmol/mg prot/h) was similar in both sexes and ten times lower than that measured in the brain of first time spawners (6.52 pmol/mg prot/h), in this case with males showing an overall higher (24%) activity than females. When surveyed throughout the year, brain AA dramatically changed during the reproductive cycle. Maximum average values of approximately 7 pmol/mg prot/h were obtained that coincided with the spawning season. The peak in brain AA was preceded by two and one months by the peak of plasma testosterone and the peak of the gonadosomatic index, respectively. This is the first measurement of the distribution of the activity of a steroidogenic enzyme in the sea bass, an established model in comparative endocrinology. Together, these results demonstrate sex- and seasonally-related variations in AA and establish the basis for further comparative studies of certain androgen-mediated actions through locally formed estrogen in both central and peripheral targets.
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Affiliation(s)
- Alicia González
- Institut de Ciències del Mar, Consejo Superior de Investigaciones, Cientifícas, Passeig Marítim, 37-49, 08003 Barcelona, Spain
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Rowell CB, Watts SA, Wibbels T, Hines GA, Mair G. Androgen and estrogen metabolism during sex differentiation in mono-sex populations of the Nile tilapia, Oreochromis niloticus. Gen Comp Endocrinol 2002; 125:151-62. [PMID: 11884061 DOI: 10.1006/gcen.2001.7691] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Androgen and estrogen metabolism were examined in the period of steroid sensitivity during sex differentiation in mono-sex populations of Oreochromis niloticus. Fry (XX, XY, and YY genotypes) were maintained at 28 degrees and were sampled at 8, 10, 11, and 13 days postfertilization. Subsamples (n = 2-4) of pooled fry from each maternally distinct family were homogenized and incubated with either [(3)H]androstenedione or [(3)H]estradiol. Metabolites present in organic extracts were identified by thin-layer chromatography, microchemical reactions, and recrystallization to constant specific activity. Androstenedione was metabolized into at least seven readily identifiable compounds by all genotypes. In the XY genotype, 5beta-androstane-3alpha,17beta-diol synthesis decreased rapidly from 8 to 13 days postfertilization, with a concomitant increase in testosterone synthesis. Testosterone synthesis did not increase in the XX genotype. Testosterone synthesis in the YY genotype was intermediate to that of the XY and XX genotypes. Estrogens were not synthesized by any genotype. We hypothesize that 5beta-reduction (or further hydroxylation) is a mechanism important in regulating testosterone production and subsequent sex differentiation. Results of incubations with estradiol show an age-dependent increase in metabolism which did not vary among genotypes. Metabolites synthesized included estrone and up to five unidentified compounds.
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Affiliation(s)
- Craig B Rowell
- Department of Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
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Lee YH, Du JL, Yen FP, Lee CY, Dufour S, Huang JD, Sun LT, Chang CF. Regulation of plasma gonadotropin II secretion by sex steroids, aromatase inhibitors, and antiestrogens in the protandrous black porgy, Acanthopagrus schlegeli Bleeker. Comp Biochem Physiol B Biochem Mol Biol 2001; 129:399-406. [PMID: 11399474 DOI: 10.1016/s1096-4959(01)00337-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Plasma gonadotropin II (GTH II) concentrations were significantly higher (approx. 15-20-fold) in estradiol-17beta (E(2)) treated (1.0 microg or 2.5 microg g(-1) body weight) female black porgy from days 4 to 12 compared with the control. E(2) (1 microg g(-1) wt.) had a stronger stimulation on plasma GTH II in early recrudescent phase (low GSI) males (11-fold) than in high GSI and late spermiating males (2.6-fold, P< 0.05). No effect of androgens (testosterone, T; 5alpha-dihydrotestosterone, DHT) on plasma GTH II levels was observed either sex. The levels of plasma GTH II were stimulated in 1,4,6-androstatriene-3,17-dione (ATD, 1 microg g(-1), 2 microg g(-1) body wt.) and fadrozole-treated (1 microg g(-1), 3 microg g(-1) body wt.) groups compared to control. Tamoxifen (1 microg g(-1), 3 microg g(-1) body wt.) but not enclomiphene could stimulate high GTH II levels in plasma. In another experiment of ATD in combination with T, T treatment further attenuated the ATD stimulation of plasma GTH II levels. We concluded that GTH II secretion is positively regulated by an estrogen-specific effect in female and male black porgy. Gonadal stage had significant effects on the responsiveness of GTH II to E(2) stimulation in males. A negative aromatase-dependent feedback control of plasma GTH II levels was also suggested in the protandrous black porgy, Acanthopagrus schlegeli.
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Affiliation(s)
- Y H Lee
- Department of Aquaculture, National Taiwan Ocean University, 202, Taiwan, Republic of, Keelung, China
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16
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Du JL, Lee CY, Tacon P, Lee YH, Yen FP, Tanaka H, Dufour S, Chang CF. Estradiol-17beta stimulates gonadotropin II expression and release in the protandrous male black porgy Acanthopagrus schlegeli Bleeker: a possible role in sex change. Gen Comp Endocrinol 2001; 121:135-45. [PMID: 11178879 DOI: 10.1006/gcen.2000.7583] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The objective of the present study was to investigate the in vivo effects of sex steroids (estradiol-17beta, E(2); testosterone, T) and the nonaromatizable androgen 5alpha-dihydrotestosterone (DHT) on the levels of gonadotropin II (GTH II) in plasma and pituitary and on aromatase activity in 2-year-old male black porgy, Acanthopagrus schlegeli, during the prereproductive season. Black porgy GTH II and GTH II beta subunits were purified and anti-GTH II beta serum was induced. A specific radioimmunoassay for black porgy GTH II was developed. cDNA GTH II beta was also cloned from a black porgy pituitary cDNA library for use as a probe for Northern analysis. Male fish were divided into eight groups (n = 64): control; E(2) (3 doses, 2.4 ng, 72 ng, and 2.2 microg/g body weight); T (2 doses, 72 ng and 2.2 microg/g body weight); and DHT (2 doses, 72 ng and 2.2 microg/g body weight). Fish were injected with the respective vehicle or different doses of material on days 0, 8, and 16. Plasma was collected at 4-day intervals from days 4 to 20. Plasma GTH II concentrations were significantly increased (up to 45-fold) in the E(2) group from days 4 to 20 in a dose-dependent manner. In a further experiment during the late reproductive season, plasma GTH II levels increased at 4 h and on days 1 and 2 following a single injection of 1.0 microg E(2)/g body weight (on day 0). Androgens (T or DHT) had little or no effect on plasma GTH II. Pituitary GTH II contents on day 20 were significantly lower in the 72-ng E(2) and 2.2-microg E(2) groups but not in the 2.4-ng E(2) group compared with the control group. Pituitary GTH II beta mRNA levels were significantly stimulated in the 72-ng and 2.2-microg E(2) groups on day 20. Gonadal aromatase activity was not significantly changed in any of the treated or control groups. It is concluded that GTH II secretion in black porgy is regulated by an estrogen-specific effect. Increased plasma GTH II levels or other factors in addition to E(2) might be involved in the regulation of gonadal aromatase activity and sex change in protandrous black porgy.
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Affiliation(s)
- J L Du
- Department of Aquaculture, National Taiwan Ocean University, Keelung 202, Taiwan, Republic of China
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17
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Abstract
In adult male and female Japanese quail, aromatase-immunoreactive cells were identified in the spinal dorsal horns from the upper cervical segments to the lower caudal area. These immunoreactive cells are located mostly in laminae I-III, with additional sparse cells being present in the medial part of lamina V and, at the cervical level exclusively, in lamina X around the central canal. Radioenzyme assays based on the measurement of tritiated water release confirmed the presence of substantial levels of aromatase activity throughout the rostrocaudal extent of the spinal cord. Contrary to what is observed in the brain, this enzyme activity and the number of aromatase-immunoreactive cells in five representative segments of the spinal cord are not different in sexually mature males or females and are not influenced in males by castration with or without testosterone treatment. The aromatase activity and the numbers of aromatase-immunoreactive cells per section are higher at the brachial and thoracic levels than in the cervical and lumbar segments. These experiments demonstrate for the first time the presence of local estrogen production in the spinal cord of a higher vertebrate. This production was localized in the sensory fields of the dorsal horn, where estrogen receptors have been identified previously in several avian and mammalian species, suggesting an implication of aromatase in the modulation of sensory (particularly nociceptive) processes.
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Affiliation(s)
- H Evrard
- Laboratory of Biochemistry, Research Group in Behavioral Neuroendocrinology, University of Liège, Liège B-4020, Belgium
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18
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Melamed P, Gur G, Rosenfeld H, Elizur A, Yaron Z. Possible interactions between gonadotrophs and somatotrophs in the pituitary of tilapia: apparent roles for insulin-like growth factor I and estradiol. Endocrinology 1999; 140:1183-91. [PMID: 10067842 DOI: 10.1210/endo.140.3.6571] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The unique organization of the teleost pituitary, in which cells are grouped according to their characteristic hormone, makes this a suitable model for studying pituitary paracrine interactions. In a number of fish, including tilapia, there are variations in the circulating levels of the gonadotropins and GH, which are elevated during the reproductive season, suggesting interactions between the reproductive and growth axes. The aim of this study was to investigate paracrine interactions between the gonadotrophs and somatotrophs in the tilapia pituitary. Initially, dispersed pituitary cells were separated on a density gradient in which the gonadotrophs were found in the least dense fractions, and the somatotrophs were concentrated in the densest fraction. After 4 days in culture, cells in the least dense fractions showed characteristic cytoplasmic extensions not seen in the somatotrophs, which appeared small and failed to form aggregates; somatotrophs were found, however, attached to other non-GH cells. Staining of the nuclei with 4,6-diaminidino-2-phenyl-dihydrochloride revealed that the isolated somatotrophs had undergone nuclear condensation and fragmentation typical of apoptosis. Addition of either estradiol or human recombinant insulin-like growth factor I (IGF-I; 10 nM) to the somatotroph cultures increased the number of cell aggregates and reduced the number of condensed or fragmented nuclei. Immunocytochemical studies on pituitary sections revealed IGF-I immunoreactivity in regions of the proximal pars distalis that stain with gonadotropin IIbeta antisera and also in regions of the rostral pars distalis characteristic of corticotrophs; immunoreactive IGF-I was never seen in the region of the somatotrophs. Incubation of cells from the different fractions with testosterone (10 nM; 24 h) revealed that cells of the least dense fractions, which were rich in gonadotrophs, possessed aromatizing ability, which was absent in the somatotroph-enriched fraction. These results suggest that estradiol and IGF-I, both generated from cells other than the somatotrophs, may exert antiapoptotic effects and thus possibly control the size of this population of cells.
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Affiliation(s)
- P Melamed
- Department of Zoology, Tel-Aviv University, Ramat Aviv, Israel
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19
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Poh LH, Munro AD, Tan CH. The Effects of Oestradiol on the Prolactin and Growth Hormone Content of the Pituitary of the Tilapia, Oreochromis mossambicus, with Observations on the Incidence of Black Males. Zoolog Sci 1997. [DOI: 10.2108/zsj.14.979] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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20
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Mol K, Byamungu N, Cuisset B, Yaron Z, Ofir M, Mélard C, Castelli M, Kühn ER. Hormonal profile of growing male and female diploids and triploids of the blue tilapia,Oreochromis aureus, reared in intensive culture. FISH PHYSIOLOGY AND BIOCHEMISTRY 1994; 13:209-218. [PMID: 24198191 DOI: 10.1007/bf00004359] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 03/29/1994] [Indexed: 06/02/2023]
Abstract
Triploidy as a result of thermal shock exposure of fertilized eggs decreases the growth rate ofOreochromis aureus as compared to their diploid controls, but this is due to the higher female ratio present in triploids (86%) and the lower growth rate of females. When females and males are considered separately, the growth rate is not significantly different in diploids and triploids. Since triploidy results in a malfunctioning steroidogenesis in females (mainly testosterone (T) and 17β-estradiol (E2)), but does not affect the growth rate, it is concluded that female gonadal steroids do not influence growth unless in pharmacological concentrations. These low levels of gonadal steroids are generally accompanied by higher levels of gonadotropin (GtH), but the difference is not always significant.Despite their lower growth rate diploid females have higher plasma concentrations of growth hormone (GH) during several months compared to the triploid females and diploid males. 3,5,3'-triiodo-L-thyronine (T3) levels, however, are comparable between diploid and triploid females (except for 1 month), but higher in diploid males in 4 of the 5 months studied. 11-ketotestosterone (11kT) is always higher in males. These results indicate that the higher growth rate of males may be related to the high circulating levels of T3 and 11kT.
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Affiliation(s)
- K Mol
- Laboratory of Comparative Endocrinology, Catholic University of Leuven, Naamsestraat 61, B-3000, Leuven, Belgium
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21
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Olivereau M, Olivereau J. Galanin-like immunoreactivity is increased in the brain of estradiol- and methyltestosterone-treated eels. HISTOCHEMISTRY 1991; 96:487-97. [PMID: 1722786 DOI: 10.1007/bf00267074] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A galanin-like peptidergic system was demonstrated in the brain of Anguilla. A group of immunoreactive perikarya was located in the nucleus preopticus periventricularis close to the recessus preopticus. Galaninergic fibers occurred in various brain areas. Galanin identified in mammalian pituitary cells was undetectable in fish adenohypophysial cells. Estradiol increased the immunostaining of the rostral perikarya and brain fibers in both male and female European eels kept in fresh water and in female American eels in sea water. Methyltestosterone, an aromatizable androgen, increased galanin immunoreactivity in rostral perikarya and brain fibers of male European eels and female American eels. The cross-sectional area of these perikarya increased significantly after both treatments whereas cell bodies of the posteroventral hypothalamus were slightly affected. Dihydrotestosterone showed no clear effect. Fibers close to the corticotropes were sometime increased, but galanin synthesis was not induced in pituitary cells. In contrast, estradiol induced galanin synthesis in rat pituitary cells, but had a still controversed effect on hypothalamic galanin. A putative influence of galanin on the pituitary-gonadal axis is discussed as gonadal hormones diversely affect gonadotropes and gonosomatic indices in Anguilla.
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Affiliation(s)
- M Olivereau
- Laboratoire de Physiologie, Institute Océanographique, Paris, France
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22
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Callard G, Schlinger B, Pasmanik M. Nonmammalian vertebrate models in studies of brain-steroid interactions. THE JOURNAL OF EXPERIMENTAL ZOOLOGY. SUPPLEMENT : PUBLISHED UNDER AUSPICES OF THE AMERICAN SOCIETY OF ZOOLOGISTS AND THE DIVISION OF COMPARATIVE PHYSIOLOGY AND BIOCHEMISTRY 1990; 4:6-16. [PMID: 1974804 DOI: 10.1002/jez.1402560404] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Estrogen formation in brain and pituitary mediates certain androgen actions in central targets. Goldfish (Carassius auratus) and quail (Coturnix coturnix japonica) have been advantageous for studying the role of locally formed estrogen in autoregulating aromatization and in controlling estrogen receptor occupancy, androgen receptor levels, and behavioral expression. Data from these two experimental models reveal a molecular basis for androgen-estrogen synergism in neuroendocrine tissues and for alterations in androgen sensitivity/responsiveness. These mechanisms are essential components of seasonal reproduction in the test species and may have wider relevance for cyclicity in other vertebrates, including mammals.
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Affiliation(s)
- G Callard
- Department of Biology, Boston University, Massachusetts 02115
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23
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Abstract
Where aromatase and estrogen receptors are co-localized in brain and pituitary, estrogen functions as a parahormone, and estrogen levels which determine the occurrence or magnitude of a response are those in close proximity to targets. Teleost fish, a vertebrate group characterized by exceptionally high aromatase in neuroendocrine tissues, are technically advantageous animal models for studying the cellular location of aromatase, natural changes correlated with seasonal reproductive cycles, substrate-dependence of the reaction, steroid induction of enzyme activity, and possible non-genomic actions of estrogen on cultured neurons. In addition, characterization of steroid receptors reveals that the androgen receptor, like aromatase, is present in unusually high concentrations (10- to 100-fold higher than in mammalian brain). Since androgen receptors and aromatase both utilize testosterone as a ligand, their high abundance in teleost brain may be the consequence of a functional interdependence during evolution, although the primary causal factor is unknown. These studies illustrate the usefulness of unconventional species and a comparative approach for obtaining new insights into brain-steroid interactions.
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Affiliation(s)
- G V Callard
- Department of Biology, Boston University, MA 02215
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