Gonadotrope plasticity at cellular, population and structural levels: A comparison between fishes and mammals

Fontaine, Romain; Ciani, Elia; Haug, Trude M.; Hodne, Kjetil; Ager-Wick, Eirill; Baker, Dianne M.; Weltzien, Finn‐Arne

doi:10.1016/j.ygcen.2019.113344

Cited by 38 publications

(30 citation statements)

References 224 publications

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“…Unlike in mammals where the different endocrine cell types are mosaically distributed in the adult anterior pituitary, in teleosts they are spatially discrete through the entire lifespan (6,11). However, in both mammals and teleosts, the anterior pituitary shows high plasticity at both cellular and population levels, allowing the anterior pituitary to meet the demands for hormonal production as they change over the life cycle of an animal (12). At the cellular level, cellular activity (hormone production and release) can be modified by varying regulatory ligand sensitivity through the presence and number of receptors, or by altering rates of hormone synthesis and secretion, the latter corresponding to the hormone release as defined by Jena (13) ( Figure 1A).…”

Section: Introductionmentioning

confidence: 99%

Direct and Indirect Effects of Sex Steroids on Gonadotrope Cell Plasticity in the Teleost Fish Pituitary

et al. 2020

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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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Section: Introductionmentioning

confidence: 99%

Direct and Indirect Effects of Sex Steroids on Gonadotrope Cell Plasticity in the Teleost Fish Pituitary

et al. 2020

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“…The utilization of transgenic animal models has greatly facilitated the study of pituitary function and plasticity. Many diverse, genomic models have been employed in identification of the roles of specific mediators of pituitary physiology and disease through the identification of effects upon whole animal physiology [for review see (2)]. Through the use of genetic models of pituitary cell type-specific leptin receptor knock-out, we have identified the mechanisms by which energy stores, as indicated through serum leptin signaling, influence pituitary function to optimize growth and reproduction.…”

Section: Continuing Discoveries; Mechanisms Mediating Cell Plasticitymentioning

confidence: 99%

“…These opposing challenges of limited cell numbers and diverse, large required outputs are resolved through plasticity in allocation of cell resources to each particular function (see Figure 1). The mechanisms controlling pituitary cell plasticity are a source of tremendous interest since these mechanisms first began to be revealed and evidence of malfunction in pituitary plasticity under diverse genetic and disease states has further motivated study to understand these mechanisms [for reviews see (1,2)]. Over the last several decades, an ongoing procession of cutting edge, novel techniques have been developed and embraced in the effort to understand pituitary function and plasticity.…”

Section: Introductionmentioning

confidence: 99%

Molecular Mechanisms of Pituitary Cell Plasticity

Childs

MacNicol

2020

Front. Endocrinol.

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The mechanisms that mediate plasticity in pituitary function have long been a subject of vigorous investigation. Early studies overcame technical barriers and challenged conceptual barriers to identify multipotential and multihormonal cell populations that contribute to diverse pituitary stress responses. Decades of intensive study have challenged the standard model of dedicated, cell type-specific hormone production and have revealed the malleable cellular fates that mediate pituitary responses. Ongoing studies at all levels, from animal physiology to molecular analyses, are identifying the mechanisms underlying this cellular plasticity. This review describes the findings from these studies that utilized state-of-the-art tools and techniques to identify mechanisms of plasticity throughout the pituitary and focuses on the insights brought to our understanding of pituitary function.

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“…Fsh and Lh are heterodimeric glycoproteins consisting of two non-covalently linked subunits, a common α-(Gpα), and a hormone-specific β-subunit (Lhβ or Fshβ) that confers the biological activity (Pierce and Parsons, 1981; Swanson et al, 2003). Unlike mammals, where both gonadotropins are produced from the same pituitary cell, Fsh and Lh in teleosts are mostly produced from two different cell types, located in the proximal pars distalis (PPD) of the pituitary gland (Fontaine et al, 2020a; Levavi-Sivan et al, 2010; Weltzien et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Sexual maturation in Atlantic salmon male parr may be triggered both in early spring and late summer under standard farming conditions

Ciani

Krogh

Nourizadeh-Lillabadi

et al. 2021

Preprint

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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 (age and season) of first sexual maturation in Atlantic salmon male parr, we investigated pubertal activation in second generation farmed salmon from the Norwegian river Figgjo, reared under natural conditions of photoperiod and water temperature. Histological analysis, in combination with morphometric measurements, plasma androgen levels and pituitary gonadotropin gene expression analysis revealed that, as previously reported, some male parr initiated early sexual maturation in spring at one year of age. Interestingly, some male parr were observed to initiate sexual maturation already in autumn, six months after hatching (under-yearlings), much earlier than reported in previous studies. One-year old maturing males showed a low induction in gonadotropin levels, while under-yearling maturing males displayed a significant increase in fshb transcripts as compared to immature fish. Plasma testosterone, detectable also in immature males, increased constantly during testes development, while 11-ketotestosterone, undetectable in immature and early maturing males, increased during more advanced stages of maturation. A mild feminization of the testes (ovotestes) was detected in a subset of samples. This study brings new knowledge on the little investigated field of sexually maturing under-yearlings in Atlantic salmon. This is also the first study comparing the physiology of under-yearling vs one-year old maturing male parr, thus bringing new insights to the remarkable plasticity of Atlantic salmon puberty.

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Gonadotrope plasticity at cellular, population and structural levels: A comparison between fishes and mammals

Cited by 38 publications

References 224 publications

Direct and Indirect Effects of Sex Steroids on Gonadotrope Cell Plasticity in the Teleost Fish Pituitary

Direct and Indirect Effects of Sex Steroids on Gonadotrope Cell Plasticity in the Teleost Fish Pituitary

Molecular Mechanisms of Pituitary Cell Plasticity

Sexual maturation in Atlantic salmon male parr may be triggered both in early spring and late summer under standard farming conditions

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