Romain Fontaine

Romain Fontaine
Norwegian University of Life Sciences (NMBU) · Department of Basic Sciences and Aquatic Medicine

PhD

About

44
Publications
15,446
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443
Citations
Introduction
Using fish as model organisms, I study components involved in the control of reproduction. I first characterise this system at molecular level using histology technics such as fluorescent in situ hybridization, immunofluorescence and confocal microscopy. I then investigate at the cellular level, using electrophysiology and calcium imaging, the interactions between the components of this system. I focus my study on the pubertal phase and in adult during the reproduction cycle.
Additional affiliations
April 2015 - November 2020
Norwegian University of Life Sciences (NMBU)
Position
  • Researcher

Publications

Publications (44)
Article
Full-text available
Dopaminergic (DA) neurons located in the preoptico-hypothalamic region of the brain exert a major neuroendocrine control on reproduction, growth and homeostasis by regulating the secretion of anterior pituitary (or adenohypophysis) hormones. Here, using a retrograde tract tracing experiment, we identified the neurons playing this role in the zebraf...
Article
Full-text available
The hormone melatonin connects environmental cues, such as photoperiod and temperature, with a number of physiological and behavioural processes, including seasonal reproduction, through binding to their cognate receptors. This study reports the structural, functional, and physiological characterization of five high‐affinity melatonin receptors (Mt...
Preprint
Full-text available
Follicle stimulating hormone (Fsh) and luteinizing hormone (Lh) produced by the gonadotropes, play a major role in control of reproduction. Contrary to mammals and birds, Lh and Fsh are mostly produced by two separate cell types in teleost. Here, we investigated gonadotrope plasticity, using transgenic lines of medaka (Oryzias latipes) where DsRed2...
Article
Full-text available
Reproductive function in vertebrates is stimulated by gonadotropin-releasing hormone (GnRH) that controls the synthesis and release of the two pituitary gonadotropins, follicle-stimulating hormone (FSH) and luteinizing hormone (LH). FSH and LH, which regulate different stages of gonadal development, are produced by two different cell types in the f...
Article
Full-text available
In vertebrates, the anterior pituitary plays a crucial role in regulating several essential physiological processes via the secretion of at least seven peptide hormones by different endocrine cell types. Comparative and comprehensive knowledge of the spatial distribution of those endocrine cell types is required to better understand their physiolog...
Article
Full-text available
The vertebrate pituitary is a dynamic organ, capable of adapting its hormone secretion to different physiological demands. In this context, endocrinologists have debated for the past 40 years if endocrine cells are mono or multi-hormonal. Since its establishment, the dominant “one cell, one hormone” model has been continuously challenged. In mammal...
Preprint
Full-text available
In fish, prolactin-producing cells (lactotropes) are located in the anterior part of the pituitary and play an essential role in osmoregulation. However, small satellite lactotrope populations have been described in other parts of the pituitary in several species. The functional and developmental backgrounds of these extra populations are not known...
Preprint
Full-text available
Japanese medaka ( Oryzias latipes ) are a teleost fish and an emerging vertebrate model for ecotoxicology, developmental, genetics, and physiology research. Medaka are also used extensively to investigate vertebrate reproduction, which is an essential biological function as it allows a species to perpetuate. Sperm quality is an important indicator...
Article
Full-text available
The pituitary is the vertebrate endocrine gland responsible for the production and secretion of several essential peptide hormones. These, in turn, control many aspects of an animal’s physiology and development, including growth, reproduction, homeostasis, metabolism, and stress responses. In teleost fish, each hormone is presumably produced by a s...
Preprint
Full-text available
Directing both organismal homeostasis and physiological adaptation, the pituitary is a key endocrine gland in all vertebrates. It communicates the needs of the organism to different organs by secreting hormones into the bloodstream. Here, we have used the model fish medaka to investigate the developmental dynamics in the pituitary using a comprehen...
Article
Full-text available
Male Atlantic salmon (Salmo salar) display different sexual strategies, maturing either as parr during the freshwater phase (as sneaky spawners), or as post smolts following one or several years at sea. First sexual maturation (puberty) occurs at different times depending on environmental and genetic factors. To improve our knowledge on the timing...
Preprint
Full-text available
In vertebrates, the anterior pituitary plays a crucial role in regulating several essential physiological processes via the secretion of at least seven peptide hormones by different endocrine cell types. Comparative and comprehensive knowledge of the spatial distribution of those endocrine cell types is required to better understand their role duri...
Article
Full-text available
In all vertebrates, the pituitary is involved in the control of many important and complex physiological processes such as growth, metabolism, homeostasis, reproduction, metamorphosis, and stress response. Located below the hypothalamus, the pituitary is divided into two main parts: the neurohypophysis (pars nervosa) and the adenohypophysis (pars d...
Preprint
Full-text available
Male Atlantic salmon (Salmo salar) display different sexual strategies, maturing either as parr during the freshwater phase (as sneaky spawners), or as post smolts following one or several years at sea. First sexual maturation (puberty) occurs at different times depending on environmental and genetic factors. To improve our knowledge on the timing...
Article
Full-text available
Accumulating evidence indicates that some pituitary cell types are organized in complex networks in both mammals and fish. In this study, we have further investigated the previously described cellular extensions formed by the medaka (Oryzias latipes) luteinizing hormone gonadotropes (Lh cells). Extensions, several cell diameters long, with varicosi...
Article
Full-text available
Melatonin is a key hormone involved in the photoperiodic signalling pathway. In both teleosts and mammals, melatonin produced in the pineal gland at night is released into the blood and cerebrospinal fluid, providing rhythmic information to the whole organism. Melatonin acts via specific receptors, allowing the synchronization of daily and annual p...
Preprint
Full-text available
The pituitary is the vertebrate endocrine gland responsible for the production and secretion of several essential peptide hormones. These, in turn, control many aspects of an animal’s physiology and development, including growth, reproduction, homeostasis, metabolism and stress responses. In teleost fish, each hormone is presumably produced by a sp...
Article
Sex steroids, produced by the gonads, play an essential role in brain and pituitary tissue plasticity and in the neuroendocrine control of reproduction in all vertebrates by providing feedback to the brain and pituitary. Teleost fishes possess a higher degree of tissue plasticity and variation in reproductive strategies compared to mammals and appe...
Article
Full-text available
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. Pitui...
Preprint
Full-text available
Sex steroids, produced by the gonads, play an essential role in the neuroendocrine control of reproduction in all vertebrates by providing feedback to the brain and pituitary. Sex steroids also play an important role in tissue plasticity by regulating cell proliferation in several tissues including the brain and the pituitary. Therefore, investigat...
Article
Full-text available
Follicle stimulating hormone (Fsh) and luteinizing hormone (Lh) produced by the gonadotropes, play a major role in control of reproduction. Contrary to mammals and birds, Lh and Fsh are mostly produced by two separate cell types in teleost. Here, we investigated gonadotrope plasticity, using transgenic lines of medaka (Oryzias latipes) where DsRed2...
Article
Full-text available
Often referred to as “the master gland”, the pituitary is a key organ controlling growth, maturation, and homeostasis in vertebrates. The anterior pituitary, which contains several hormone-producing cell types, is highly plastic and thereby able to adjust the production of the hormones governing these key physiological processes according to the ch...
Article
Full-text available
Reproductive function in vertebrates is stimulated by gonadotropin-releasing hormone (GnRH) that controls the synthesis and release of the two pituitary gonadotropins, follicle-stimulating hormone (FSH) and luteinizing hormone (LH). FSH and LH, which regulate different stages of gonadal development, are produced by two different cell types in the f...
Preprint
Full-text available
Accumulating evidence in the scientific literature indicates that some pituitary cell types are organized in complex networks. Previous observations have indicated that this may also be the case in medaka (Oryzias latipes), where long cellular extensions with varicosity-like swellings are formed by luteinizing hormone (Lh)-producing gonadotropes ex...
Preprint
Full-text available
Reproductive function in vertebrates is stimulated by gonadotropin-releasing hormone (GnRH) that controls the synthesis and release of the two pituitary gonadotropins, follicle-stimulating hormone (FSH) and luteinizing hormone (LH). FSH and LH, which regulates different stages of gonadal development, are produced by two different cell types in the...
Article
Full-text available
Gonadotropin-releasing hormone (Gnrh) plays a major role in the regulation of physiological and behavioural processes related to reproduction. In the pituitary, it stimulates gonadotropin synthesis and release via activation of Gnrh receptors (Gnrhr), belonging to the G protein-coupled receptor superfamily. Evidence suggests that differential regul...
Article
Full-text available
Background: The impossibility of closing the life cycle of the European eel (Anguilla anguilla) in captivity troubles the future of this critically endangered species. In addition, the European eel is a highly valued and demanded resource, thus the successful closing of its life cycle would have a substantial economic and ecological impact. With t...
Article
Blood vessels innervate all tissues in vertebrates, enabling their survival by providing the necessary nutrients, oxygen, and hormonal signals. It is one of the first organs to start functioning during development. Mechanisms of blood vessel formation have become a subject of high scientific and clinical interest. In adults however, it is difficult...
Article
Full-text available
The paucity of information on understanding the regulatory mechanisms that are involved in the control of piscine Fsh and Lh synthesis, secretion, and function, prompted the present work. Part of the problem is related to the molecular heterogeneity and the unavailability of Fsh and Lh assays for quantifying gonadotropins, in particular assays rega...
Article
Full-text available
Smoltification is a metamorphic event in salmon life history, which initiates downstream migration and pre-adapts juvenile salmon for seawater entry. While a number of reports concern thyroid hormones and smoltification, few and inconclusive studies have addressed the potential role of thyrotropin (TSH). TSH is composed of a α-subunit common to gon...
Article
Full-text available
Luteinizing hormone (Lh) and follicle-stimulating hormone (Fsh) control reproduction in vertebrates. Using a transgenic line of medaka, in which green fluorescent protein expression is controlled by the endogenous lhb promotor, we studied development and plasticity of Lh cells, comparing juveniles and adults of both genders. Confocal imaging and 3D...
Article
Full-text available
The gonadotropins follicle-stimulating hormone (Fsh) and luteinizing hormone (Lh) play essential roles in vertebrate reproduction. This article presents data on molecular weight validation of recombinant medaka (Oryzias latipes) (md) gonadotropins Fshβ (mdFshβ), Lhβ (mdLhβ), Fshβα (mdFshβα), and Lhβα (mdLhβα) generated by Pichia pastoris, as well a...
Article
The two gonadotropins follicle-stimulating hormone (Fsh) and luteinizing hormone (Lh) are of particular importance within the hypothalamic-pituitary-gonadal (HPG) axis of vertebrates. In the current study, we demonstrate the production and validation of Japanese medaka (Oryzias latipes) recombinant (md) gonadotropins Fshβ (mdFshβ), Lhβ (mdLhβ), Fsh...
Article
Primary cell culture is a powerful tool commonly used by scientists to study cellular properties and mechanisms of isolated cells in a controlled environment. Despite vast differences in the physiology between mammals and fish, primary cell culture protocols from fish are often based on mammalian culture conditions, often with only minor modificati...
Article
Electrophysiological investigations of pituitary cells have been conducted in numerous vertebrate species, but very few in teleost fish. Among these, the clear majority have been performed on dissociated primary cells. To improve our understanding of how teleost pituitary cells, behave in a more biologically relevant environment, this protocol show...
Poster
Manipulation of photoperiod and temperature are used to optimize production through enhancement of growth and maturation of fish species. Knowledge on how photoperiod and temperature affect maturation and sperm quality is limited. However, studies about sperm behaviour and environment (temperature, photoperiod, etc.) effects on fish sperm quality a...
Article
Full-text available
Cerebrospinal fluid-contacting (CSF-c) cells containing monoamines such as dopamine (DA) and serotonin (5-HT) occur in the periventricular zones of the hypothalamic region of most vertebrates except for placental mammals. Here we compare the organization of the CSF-c cells in chicken, Xenopus, and zebrafish, by analyzing the expression of synthetic...
Article
Full-text available
In vertebrates, the regulation of gametogenesis is under the control of gonadotropins (Gth), follicle-stimulating hormone (Fsh) and luteinizing hormone (Lh). In fish, the physiological role of Gths is not fully understood, especially in species with asynchronous ovarian development. In order to elucidate the role of Gths in species with asynchronou...
Article
Full-text available
Dopamine neurotransmission regulates various brain functions, and its regulatory roles are mediated by two families of G protein-coupled receptors: the D1 and D2 receptor families. In mammals, the D1 family comprises two receptor subtypes (D1 and D5), while the D2 family comprises three receptor subtypes (D2, D3 and D4). Phylogenetic analyses of do...
Thesis
Full-text available
C’est chez un téléostéen qu’il a été démontré pour la première fois que le contrôle stimulateur de l’axe gonadotrope par la GnRH peut être contrebalancé par un contrôle inhibiteur assuré par la dopamine (DA). Ce contrôle dopaminergique inhibiteur a été retrouvé par la suite chez diverses espèces de vertébrés. Cependant l’importance fonctionnelle de...
Article
Full-text available
In many teleosts, the stimulatory control of gonadotrope axis by GnRH is opposed by an inhibitory control by dopamine (DA). The functional importance of this inhibitory pathway differs widely from one teleostean species to another. The zebrafish (Danio rerio) is a teleost fish that has become increasingly popular as an experimental vertebrate model...

Questions

Question (1)
Question
Hello, I looking for studies that have investigated, the time delay between the end of the expression of a fluorescent reporter gene and the loss of the fluorescence in the cell.
I know that fluorescent proteines such as Gfp and Rfp are quite stable and thus should not be used to quantify the transcription of an interesting gene in time. But I would like to get an idea on how long the cell will stay fluorescent after the cell stoped to produced the mRNA.
Thank you in advance for your help

Projects

Projects (4)
Project
The plan is to produce an 3D atlas of the medaka (Oryzias latipes) pituitary
Archived project
Study of the dopaminergic inhibitory system controlling reproduction in zebrafish.
Project
Study how the pituitary can evolve to answer to the hormone demand which differs according to the life cycle