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Journal ArticleDOI

A systematic immunohistochemical survey of the distribution patterns of GH, prolactin, somatolactin, β–TSH, β–FSH, β–LH, ACTH, and α–MSH in the adenohypophysis of Oreochromis niloticus, the Nile tilapia

22 Mar 2006-Cell and Tissue Research (Springer-Verlag)-Vol. 325, Iss: 2, pp 303-313
TL;DR: A complete map of the distinct localisation sites for the classical pituitary hormones is presented, thereby providing a solid basis for future research on teleost pituitaries.
Abstract: Fish pituitary plays a central role in the control of growth, development, reproduction and adaptation to the environment. Several types of hormone-secreting adenohypophyseal cells have been characterised and localised in diverse teleost species. The results suggest a similar distribution pattern among the species investigated. However, most studies deal with a single hormone or hormone family. Thus, we studied adjacent sections of the pituitary of Oreochromis niloticus, the tilapia, by conventional staining and immunohistochemistry with specific antisera directed against growth hormone (GH), prolactin (PRL), somatolactin (SL), thyrotropin (beta-TSH), follicle-stimulating hormone (beta-FSH), luteinising hormone (beta-LH), adrenocorticotropic hormone (ACTH) and melanocyte-stimulating hormone (alpha-MSH). The pituitary was characterised by a close interdigitating neighbourhood of neurohypophysis (PN) and adenohypophysis. PRL-immunoreactive and ACTH-immunoreactive cells were detected in the rostral pars distalis. GH-immunoreactive cells were present in the proximal pars distalis (PPD). A small region of the PPD contained beta-TSH-immunoreactive cells, and beta-LH-immunoreactive cells covered approximately the remaining parts. Centrally, beta-FSH-immunoreactive cells were detected in the vicinity of the GH-containing cells. Some of these cells also displayed beta-LH immunoreactivity. The pars intermedia was characterised by branches of the PN surrounded by SL-containing and alpha-MSH-immunoreactive cells. The ACTH and alpha-MSH antisera were observed to cross-react with the respective antigens. This cross-reactivity was abolished by pre-absorption. We present a complete map of the distinct localisation sites for the classical pituitary hormones, thereby providing a solid basis for future research on teleost pituitary.

Summary (2 min read)

Introduction

  • As in mammals, fish pituitary has been described to play a central regulatory role in the control of growth, development, reproduction and adaptation to environmental challenges, such as changes in salinity, temperature and stress.
  • Whereas the hormone– producing cell types are arranged in a mosaic pattern in the pituitary of adult tetrapods, teleost pituitary preserves the embryonic compartmental organisation, i.e. each specific hormone–producing cell type is located in a particular compartment.

Materials and methods

  • Fish culture Twelve individuals of Oreochromis niloticus (125 days old) kindly provided by Prof. N. Maclean (School of Biological Sciences, University of Southampton, Southampton, UK), and Dr. J.-F. Baroiller (CIRAD, Montpellier, France) were used.
  • For semi-thin sections, pituitaries were fixed by immersion in a solution containing 2.5% paraformaldehyde, 0.1% glutaraldehyde and 0.01% picric acid for 4 h.
  • For haematoxylin–eosin (HE) staining, slides were immersed in Mayer`s haematoxylin for 10 min, briefly treated with HCl solution, rinsed in tap water for 10 min and subsequently immersed in eosin for another 10 min.
  • Slides were dehydrated in 100% ethanol and xylol (all reagents obtained from Fluka, Switzerland) and covered with Eukitt (Merck, Switzerland).
  • In contrast, for the antichum-salmon gonadotropin antisera, the reported cross– reactivities (see Introduction) could not be abolished by pre–absorption (Nozaki et al. 1990), whereas no immunostaining was observed after pre–incubation of the antihuman β–FSH and β–TSH antisera with an excess of the appropriate antigens (Grandi and Chicca 2004).

Results

  • Structure of the pituitary of adult O. niloticus Consecutive sagittal Paraplast sections of tilapia pituitary attached to the brain were stained with HE (Fig. 1a) and PAS (Fig. 1b).
  • Distribution pattern of tilapia adenohypophyseal hormones analysed by immunofluorescence microscopy Consecutive sections to Fig. 1 were investigated by using antisera (Table 1) specific for the classical adenohypophyseal hormones, i.e. members of the GH/PRL family (GH, PRL, SL), the glycoprotein hormone group constituted by the gonadotropins and thyrotropin (β–FSH, β–LH, β– TSH) and members of the proopio–melanocorticotropin (POMC) family (ACTH, α–MSH).
  • GH–immunoreactive cells were arranged in regular chains along the branches of the PN within the PPD (Fig. 2b).
  • Similar results were achieved by immunocytochemistry on horizontal semi-thin sections (Fig. 3c–f): anti-chum-salmon (Fig. 3c) and anti-human (Fig. 3d) β–LH antisera displayed an identical staining pattern in the PPD, and the anti-chumsalmon β–FSH antiserum (Fig. 3e) again recognised the same regions as the β–LH antisera.
  • Accordingly, cross-reactivity of the ACTH antiserum to α–MSH cells (Fig. 4d) in the PI was strongly reduced by preincubation of the anti–ACTH antiserum with α–MSH at 40 μg/ml (Fig. 4e) and completely abolished at 400 μg/ml (Fig. 4f) antiserum.

Discussion

  • An understanding of the central role of the adenohypophysis in teleosts (for a recent review, see Agulleiro et al. 2006) demands profound knowledge of the distribution of the hormone–producing cells.
  • The authors assume that the restriction of GH cells to the PPD is characteristic for adult fish and their wide–spread occurrence for developing fish.
  • In their study, the antisera directed against human β–LH and chum salmon β–LH give identical staining patterns.

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Year:2006
Asystematicimmunohistochemicalsurveyofthedistributionpatternsof
GH,prolactin,somatolactin,฀–TSH,฀–FSH,฀–LH,ACTH,and฀–MSHinthe
adenohypophysisofOreochromisniloticus,theNiletilapia
Kasper,RS;Shved,N;Takahashi,A;Reinecke,M;Eppler,E
Abstract:Fishpituitaryplaysacentralroleinthecontrolofgrowth,development,reproductionandadap-
tationtotheenvironment.Severaltypesofhormone-secretingadenohypophysealcellshavebeencharac-
terisedandlocalisedindiverseteleostspecies. Theresultssuggestasimilardistributionpatternamong
thespeciesinvestigated.However,moststudiesdealwithasinglehormoneorhormonefamily.Thus,
westudiedadjacentsectionsofthepituitaryofOreochromisniloticus,thetilapia,byconventionalstain-
ingandimmunohistochemistrywithspecicantiseradirectedagainstgrowthhormone(GH),prolactin
(PRL),somatolactin(SL),thyrotropin(beta-TSH),follicle-stimulatinghormone(beta-FSH),luteinising
hormone(beta-LH),adrenocorticotropichormone(ACTH)andmelanocyte-stimulatinghormone(alpha-
MSH). Thepituitary wascharacterisedby aclose interdigitatingneighbourhood ofneurohypophysis
(PN)and adenohypophysis.PRL-immunoreactiveand ACTH-immunoreactivecells weredetected in
therostralparsdistalis.GH-immunoreactivecellswerepresentintheproximalparsdistalis(PPD).A
smallregionofthePPDcontainedbeta-TSH-immunoreactivecells,andbeta-LH-immunoreactivecells
coveredapproximatelytheremainingparts.Centrally,beta-FSH-immunoreactivecellsweredetectedin
thevicinityoftheGH-containingcells.Someofthesecellsalsodisplayedbeta-LHimmunoreactivity.
TheparsintermediawascharacterisedbybranchesofthePNsurroundedbySL-containingandalpha-
MSH-immunoreactivecells.TheACTHandalpha-MSHantiserawereobservedtocross-reactwiththe
respectiveantigens. Thiscross-reactivitywasabolishedbypre-absorption.Wepresentacompletemap
ofthedistinctlocalisationsitesfortheclassicalpituitaryhormones,therebyprovidingasolidbasisfor
futureresearchonteleostpituitary.
DOI:https://doi.org/10.1007/s00441-005-0119-7
PostedattheZurichOpenRepositoryandArchive,UniversityofZurich
ZORAURL:https://doi.org/10.5167/uzh-29959
JournalArticle
PublishedVersion
Originallypublishedat:
Kasper,RS;Shved,N;Takahashi,A;Reinecke,M;Eppler,E(2006).Asystematicimmunohistochemical
surveyofthedistributionpatternsofGH,prolactin,somatolactin,฀–TSH,฀–FSH,฀–LH,ACTH,and฀–
MSHin theadenohypophysisof Oreochromisniloticus, theNiletilapia.Cell andTissue Research,
325(2):303-313.
DOI:https://doi.org/10.1007/s00441-005-0119-7

Cell Tissue Res (2006) 325: 303313
DOI 10.1007/s00441-005-0119-7
REGULAR ARTICLE
Romano Silvio Kasper
.
Natallia Shved
.
Akiyoshi Takahashi
.
Manfred Reinecke
.
Elisabeth Eppler
A systematic immunohistochemical survey of the distribution
patterns of GH, prolactin, somatolactin, βTSH, βFSH,
βLH, ACTH, and αMSH in the adenohypophysis
of
Oreochromis niloticus
, the Nile tilapia
Received: 24 June 2005 / Accepted: 3 November 2005 / Published online: 22 March 2006
# Springer-Verlag 2006
Abstract Fish pituitary plays a central role in the control of
growth, development, reproduction and adaptation to the
environment. Several types of hormonesecreting adeno-
hypophyseal cells have been characterised and localised in
diverse teleost species. The results suggest a similar distri-
bution pattern among the species investigated. However,
most studies deal with a single hormone or hormone family.
Thus, we studied adjacent sections of the pituitary of
Oreochromis niloticus, the tilapia, by conventional staining
and immunohistochemistry with specific antisera directed
against growth hormone (GH), prolactin (PRL), somatolactin
(SL), thyrotropin (βTSH), folliclestimulating hormone
(βFSH), luteinising hormone (βLH), adrenocorticotropic
hormone (ACTH) and melanocytestimulating hormone
(αMSH). The pituitary was characterised by a c lose in-
terdigitating neighbourhood of neurohypophysis (PN) and
adenohypophysis. PRLimmunoreactive and ACTHim-
munoreactive cells were detected in the rostral pa rs
distalis. GHimmunoreactive cells were present in the
proximal pars distalis (PPD). A small region of the PPD
contained βTSHimmunoreactive cells, and βLHim-
munoreactive cells covered approximately the remaining
parts. Centrally, βFSHimmunoreactive cells were de-
tected in the vicinity of the GHc ontaining cel ls. Some of
these cells also displayed βLH immunoreactivity. The
pars intermedia was characterised by branches of the PN
surroundedbySLcontaining and αMSHimmunoreac-
tive cells.The ACTH and αMSH antisera were observed
to cross-react with the respective antigens. This cross
reactivity was abolished by preabsorption. We present a
complete map of the distinct localisation sites for the
classical pituitary hormones, thereby providing a solid
basis for future research on teleost pituitary.
Keywords Pituitary
.
Hormones
.
Localisation
.
Immunohistochemistry
.
Mapping
.
Teleost
Introduction
As in mammals, fish pituitary has been described to play a
central regulatory role in the control of growth, develop-
ment, reproduction and adaptation to environmental
challenges, such as changes in salinity, temperature and
stress. Bony fish represent the largest non-mammalian
vertebrate group and provide valuable models for basic
research on vertebrate physiology. In addition, numerous
bony fish species, such as salmonids, seabream and tilapia,
have high commercial value and are used in aquaculture,
the fastest growing area of food production. Therefore, the
scientific results on the regulatory mechanisms involved in
growth, development and reproduction that have emerged
are of major impact not only in basic science, but also in the
aquaculture industry (for reviews, see Reinecke and Collet
1998; Reinecke et al. 2005). The susceptibility of fish kept
in pond culture or other farming conditions to environ-
mental challenges, including pollutants, is an important
research field that is increasingly under investigation.
In teleosts, the pituitary is characterised by a close
interdigitating neighbourhood between the neurohypophy-
sis (pars nervosa, PN) and the adenohypophysis. The latter
consists of three main parts: the rostral pars distalis (RPD),
the proximal pars distalis (PPD), and the pars intermedia
This work was supported by the SNF (NRP 50, project 4050
66580) and by the Hartmann Müller-Stiftung für Medizinische
Forschung an der Universität Zürich (grant no. 972).
R. S. Kasper
.
N. Shved
.
M. Reinecke
.
E. Eppler (*)
Division of Neuroendocrinology, Institute of Anatomy,
University of Zürich,
Winterthurerstrasse 190,
Zürich CH8057, Switzerland
e-mail: eppler@anatom.unizh.ch
Tel.: +41-44-6355333
Fax: +41-44-6355702
A. Takahashi
Laboratory of Molecular Endocrinology,
School of Fisheries Sciences, Kitasato University,
Ofunato, Iwate, Japan

(PI). Unlike mammals, teleost fish lack a hypothalamo
hypophyseal portal system for the transport of neurohor-
monal regulators. Instead, a direct axonal transport exists
between hypothalamic neurons and pituitary endocrine
cells via the hypophyseal stalk and the PN (Weltzien et al.
2004).
The hormoneproducing cells of the adenohypophysis
have been investigated for several decades by means of
standard staining procedures and immunocytochemical and
molecular biological methods (for a review, see Agulleiro
et al.
2006). With these methods, hormonesecreting
adenohypophyseal cells have been characterised and lo-
calised in diverse teleost species. Whereas the hormone
producing cell types are arranged in a mosaic pattern in the
pituitary of adult tetrapods, teleost pituitary preserves the
embryonic compartmental organisation, i.e. each specific
hormoneproducing cell type is located in a particular
compartment. Thus, teleost fish represent interesting mod-
els for the study of pituitary ontogeny and phylogeny (for a
review, see Weltzien et al.
2004).
The potential impact of environmental pollutants on
growth hormone (GH) and adrenocorticotropic hormone
(ACTH) peptide expression has been pointed out in tilapia
(Oreochromis niloticus) indicating the need for further
studies (Mousa and Mousa
1999a). However, few system-
atic data exist on teleost pituitary as the central regulatory
organ of numerous physiological processes. Most studies
deal with single hormones or hormone families (e.g.
Amemiya et al.
1999; Amano et al. 2005; Dores et al.
1996; García Ayala et al. 2003; Huang and Specker 1994;
Joss et al.
1990; Kagawa et al. 1998; Kawauchi et al. 1986,
1989; Mousa and Mousa 1999a,b; Nagahama et al. 1981;
Naito et al.
1983; Nishioka et al. 1993; Nozaki et al. 1990;
Olivereau and Rand-Weaver
1994; Parhar et al. 2003;
Power
1992; Rand-Weaver et al. 1991; Saga et al. 1993;
Shimizu et al.
2003; Siegmund et al. 1987; Weltzien et al.
2003a). A few more extensive studies have been performed
(e.g. García-Hernández et al.
1996; Grandi and Chicca
2004; Laiz-Carrión et al. 2003; Naito et al. 1993; Parhar et
al.
1998, 2002; Sánchez Cala et al. 2003; Segura-Noguera
et al.
2000; Weltzien et al. 2003b; Yan and Thomas 1991
)
but no thorough investigation has localised all pituitary
hormones by immunohistochemistry on consecutive sections.
In detail, during the ontogeny of chum salmon
(Oncorhynchus keta), cells expressing ACTH, prolactin
(PRL), GH, αmelanocytestimulating hormone (αMSH)
and βthyroidstimulating hormone (βTSH) have been
localised by using immunocytochemistry (Naito et al.
1993). In the protogynous teleost wrasse Thalassoma
duperrey, all adenohypophyseal hormones were investi-
gated but cross-reactivities between βTSH and the gonad-
otropin GTH II (βLH) antisera had to be considered
(Parhar et al.
1998); however, the study mainly character-
ised endocrine cells at the ultrastructural level and only
selected hormones were presented by light microscopy. In
an ontogenic study on sturgeon, Acipenser naccarii, the
appearance and distribution of all adenohypophyseal hor-
mones including βendorphin were monitored but, as the
main focus was laid on early development, the demand for
investigations of the hormone expression pattern in adults
was stressed (Grandi and Chicca
2004).
An early study of adult Atlantic croaker (Micropogonias
undulatus), spotted sea trout (Cynoscion nebulosus) and red
drum (Sciaenops ocellatus) investigated the cells express-
ing GH, PRL, ACTH, βTSH and the gonadotropins but
the distinct localisation of the gonadotropins remained
unclear (Yan and Thomas
1991). An immunocytochemical
study in Mediterranean yellowtail (Seriola dumerilii)
characterised the same hormonal cell types, plus SL and
αMSH. Again, the gonadotropins could not be defin-
itively localised (García-Hernández et al.
1996). Similarly,
in young white seabream (Diplodus sargus), the data for the
gonadotropins also remained unclear (Segura-Noguera et
al.
2000). In a more recent study in adult male Atlantic
halibut (Hippoglossus hippoglossus), a map was created for
the distinct localisations of all hormone cell types, whereby
βFSH was localised by in situ hybridisation (Weltzien et
al.
2003b). However, a clear interpretation of the potential
colocalisation of the gonadotropins was not possible. In a
study on gonadotropinreleasing hormone receptors re-
cently performed in tilapia, the gonadotropins and cells of
the GH/PRL family were also investigated by using in situ
hybridisation and immunohistochemistry; whereas β
LH
containing cells were displayed at the gene and peptide
expression level, βFSHexpressing cells were again
detected exclusively at the mRNA level (Parhar et al.
2002). The contradictory results led to the explanation that
the antisera against salmon βFSH might recognise an
epitope of tilapia βLH (Parhar et al.
2003), a proposal that
gives new support to the importance of a definite localisa-
tion of the gonadotropins, especially with respect to the
differences in sexual regulation between salmonids and
nonsalmonids.
Thus, to our knowledge, no study has as yet succeeded in
demonstrating all the hormone-producing cells in the entire
pituitary in adjacent or, at least similarly oriented, sections
by using the same technique consistently throughout the
investigation. However, only this approach can create a
basis for investigations of diverse hormoneproducing
cells under various experimental settings. Furthermore, no
complete mapping has been performed in tilapia, a species
widely used in aquaculture. Another problem that has not
been sufficiently addressed to date is the dual existence and
localisation of the gonadotropins, i.e. GTH I and GTH II,
more recently shown to be β FSH and βLH in higher
teleosts (Rosenfeld et al.
2001; Quérat et al. 1990). The
obtained contradictory results (see above) have been
attributed not only to species differences, but also to
antiseradependent differences (e.g. García-Hernández et
al.
1996; Segura-Noguera et al. 2000; Parhar et al. 2003)
and need to be clarified.
In order to provide a basis for future experiments, we
wanted to elaborate a defined morphological knowledge of
teleost pituitary and thus explored the pituitary of the Nile
tilapia (O. niloticus) as a representative model species.
Thus, the distribution pattern of GH, PRL and SL, of the
POMC family members ACTH and αMSH, and of
βTSH and the gonadotropins βFSH and βLH was
304

analysed on consecutive Paraplast and semi-thin sections.
Special emphasis was laid on elucidating the localisation
sites of the gonadotropins βFSH and βLH. Based on the
results obtained, we finally obtained a complete map of the
distinct localisation sites of all pituitary hormones.
Materials and methods
Fish culture
Twelve individuals of Oreochromis niloticus (125 days
old) kindly provided by Prof. N. Maclean (School of
Biological Sciences, University of Southampton, South-
ampton, UK), and Dr. J.-F. Baroiller (CIRAD, Montpellier,
France) were used. The fish were kept in fresh-water tanks
at 27±1°C under a 12 h/12 h light/dark cycle and fed to
satiation.
Tissue sampling and preparation
Fish were anaesthetised with 2phenoxyethanol (Sigma,
St. Louis, Mo, USA) added to the water and killed.
Pituitaries were immediately excised and, for conventional
and immunofluoresence microscopy, attachment to the
brain was conserved to simplify later orientation. Tissue
samples were fixed by immersion in acetic-acid-free
Bouins solution for 4 h at room temperature. Specimens
were dehydrated in an ascending series of ethanol and
routinely embedded in Paraplast Plus at 58°C. Sections
were cut at 4 μm, mounted on Super Frost Plus slides
(MenzelGläser, Germany) and dried overnight at 42°C.
After being dewaxed in xylol, they were rehydrated in a
descending series of ethanol (100%, 96%, 70%).
For semi-thin sections, pituitaries were fixed by immer-
sion in a solution containing 2.5% paraformaldehyde, 0.1%
Table 2 HE and PAS staining (PI pars intermedia, PN pars nervosa,
PPD proximal pars distalis, RPD rostral pars distalis)
Hormone Region HE stain PAS stain
ACTH RPD Basophilic Negative
βFSH PPD Basophilic Positive
GH PPD Strongly eosinophilic Negative
βLH PPD Basophilic Positive
αMSH PI Basophilic Negative
PRL RPD Strongly eosinophilic Negative
SL PI Eosinophilic Negative
βTSH PPD Basophilic Positive
Fig. 1 Histology of tilapia pituitary. Consecutive sagittal Paraplast
sections stained with (a) HE and (b) PAS (see Table
2). a, b The
adenohypophysis is divided into three main parts, the rostral (RPD)
and proximal (PPD) pars distalis and the pars intermedia (PI).
Sections display the neural connection of the hypothalamus to the
pituitary (a, arrows) and the interdigitating branches of the PN
reaching the PI (b, arrowheads). b Regions containing cells
expressing ACTH (c) and αMSH (d) investigated by the pre
absorption experiment (see Fig.
4). Bar 150 μm
Table 1 Primary antisera used for immunofluorescence on Paraplast sections (all antisera raised in rabbit)
Antiserum against Specificity Dilutions Source Reference
ACTH (123) Rat 1:2,000 Peptide Inst., Osaka (Japan), cat. no. Y352
FSH, βsubunit Chum salmon 1:400 Dr. H. Kawauchi, Kitasato University (Japan), lot 8510 Nozaki et al.
1990
FSH, βsubunit Human 1:100 Biogenesis, Poole (England), cat. no. 45608055 Grandi and Chicca 2004
GH Chum salmon 1:8,000 Dr. H. Kawauchi, Kitasato University (Japan), lot 8502 Kawauchi et al. 1986
LH, βsubunit Chum salmon 1:4,000 Dr. H. Kawauchi, Kitasato University (Japan), lot 8506 Nozaki et al. 1990
LH, βsubunit Human 1:200 DAKO A/S, Glastrup, Denmark, cat. no. N1543 Siegmund et al. 1987
MSH, αsubunit Human 1:1,500 Biogenesis, Poole (England), cat. no. 60450400 Amano et al. 2005
PRL Chum salmon 1:12,000 Dr. H. Kawauchi, Kitasato University (Japan), lot 8206 Naito et al. 1983
SL Chum salmon 1:4,000 Dr. H. Kawauchi, Kitasato University (Japan), lot 8906 Rand-Weaver et al. 1991
TSH, βsubunit Human 1:300 Biogenesis, Poole (UK), cat. no. 89260004 Grandi and Chicca 2004
305

glutaraldehyde and 0.01% picric acid for 4 h. Thereafter,
specimens were dehydrated in an ascending series of
ethanol and routinely embedded in LR White (Poly-
sciences, Warrington, USA). Serial semi-thin sections
(1 μm) were cut on an Ultracut E (Reichert-Jung, Zürich,
Switzerland) and placed on glass slides.
Haematoxylineosin and periodicacidSchiff stain
For haematoxylineosin (HE) staining, slides were im-
mersed in Mayer`s haematoxylin for 10 min, briefly treated
with HCl solution, rinsed in tap water for 10 min and
subsequently immersed in eosin for another 10 min. For
periodicacidSchiff (PAS) staining, slides were treated
with periodic acid for 5 min and rinsed in tap water.
Treatment with Schiffs reagent for 15 min was followed
by exposure of the sections to sodium bisulfite (0.52%) for
10 min. After a rinse in tap water, slides were immersed in
Mayers haematoxylin. After another wash step, differen-
tiation in HCl ethanol was performed followed by a rinse in
flowing water. Slides were dehydrated in 100% ethanol and
xylol (all reagents obtained from Fluka, Switzerland) and
covered with Eukitt (Merck, Switzerland).
Fig. 2 Localisation of hor-
mones in tilapia pituitary by the
use of immunofluorescence.
Eight consecutive sagittal Para-
plast sections adjacent to Fig. 1
were stained with specific anti-
sera raised in rabbit (see Table
1)
and visualised with an FITC-
coupled anti rabbit IgG (PI pars
intermedia, PN pars nervosa,
PPD proximal pars distalis, RPD
rostral pars distalis). ac Anti-
sera directed against chum
salmon (a) PRL, (b) GH, (c) SL.
d Antibody directed against
human TSH βsubunit.
e Anti-chum-salmon βLH an-
tiserum. f Anti-human βFSH
antiserum. g, h Antibodies di-
rected against (g) rat ACTH
(amino acids 123) and (h)
human MSH αsubunit. Bar
200 μm
306

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  • ...However, co-localization of LH and FSH in gonadotropes has been demonstrated in Nile tilapia, and the presence of distinct FSH- and LH-producing cells cannot be demonstrated in white seabream and several other fish species (Kasper et al., 2006; Pandolfi et al., 2006; and references therein)....

    [...]

Journal ArticleDOI
TL;DR: In this paper, the hypothalamic pro-opiomelanocortin and AgRP neurons are hypophysiotropic, projecting to the pituitary to coordinately regulate multiple pituitaries hormones.

80 citations

References
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Journal ArticleDOI
TL;DR: This communication summarizes viewpoints, discussion, perspectives, and questions, put forward at a workshop on "Growth hormone and insulin-like growth factors in fish" held on September 7th, 2004, at the 5th International Symposium on Fish Endocrinology in Castellon, Spain.

374 citations


"A systematic immunohistochemical su..." refers background in this paper

  • ...Therefore, the scientific results on the regulatory mechanisms involved in growth, development and reproduction that have emerged are of major impact not only in basic science, but also in the aquaculture industry (for reviews, see Reinecke and Collet 1998; Reinecke et al. 2005)....

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01 Jan 2005
TL;DR: Bjornsson et al. as mentioned in this paper summarized viewpoints, discussion, perspectives, and questions, put forward at a workshop on Growth Hormone and insulin-like growth factors in Wsh.
Abstract: This communication summarizes viewpoints, discussion, perspectives, and questions, put forward at a workshop on “Growthhormone and insulin-like growth factors in Wsh” held on September 7th, 2004, at the 5th International Symposium on Fish Endocri-nology in Castellon, Spain. 2005 Elsevier Inc. All rights reserved. Keywords: Growth Hormone and insulin -like growth factors in Wsh 1. Growth hormone Growth hormone (GH) is a pluripotent hormone pro-duced by the pituitary gland in teleosts as in other verte-brates. GH brings about its action by binding to a singlepass-transmembrane receptor, the GH receptor (GHR),in target tissue. Ligand binding induces receptor dimer-ization producing an active trimeric complex (for review,see Perez-Sanchez et al., 2002). GH has been sequencedand/or the protein isolated from scores of teleosts, vari-ous immunoassays established, and a number of GH-transgenic Wsh strains established. Over the last twodecades, many aspects of GH physiology have been thesubject of intense research in Wsh such as the salmonids,cyprinids, and sparids. In Wsh, GH participates in almostall major physiological processes in the body includingthe regulation of ionic and osmotic balance, lipid, pro-tein, and carbohydrate metabolism, skeletal and soft tis-sue growth, reproduction and immune function. Recentstudies have indicated that GH aVects several aspects ofbehaviour, including appetite, foraging behaviour,aggression, and predator avoidance, which in turn hasecological consequences (for reviews, see Bjornsson,1997; Bjornsson et al., 2004; Perez-Sanchez, 2000; Peterand Marchant, 1995).Despite the vast body of knowledge which exists doc-umenting GH action in teleost Wsh, the mode of GHaction remains a major discussion topic (for review, seeBjornsson et al., 2004). Generalized claims have beenmade that most/all GH eVects are indirect, based on anoutdated mammalian view where the pituitary/hepaticGH/IGF-I system was seen as an “axis” with IGF-Imediating the physiological action of GH (for review,see Bjornsson et al., 2004; Butler and Le Roith, 2001).

336 citations

Journal ArticleDOI
TL;DR: The present status on the male teleost BPG axis, with an emphasis on flatfish, is reviewed, and some entirely new information on the phylogeny and molecular structure of teleost gonadotropins is presented.
Abstract: The key component regulating vertebrate puberty and sexual maturation is the endocrine system primarily effectuated along the brain-pituitary-gonad (BPG) axis. By far most investigations on the teleost BPG axis have been performed on salmonids, carps, catfish and eels. Accordingly, earlier reviews on the BPG axis in teleosts have focused on these species, and mainly on females (e.g. 'Fish Physiology, vol. IXA. Reproduction (1983) pp. 97'; 'Proceedings of the Fourth International Symposium on the Reproductive Physiology of Fish. FishSymp91, Sheffield, UK, 1991, pp. 2'; 'Curr. Top. Dev. Biol. 30 (1995) pp. 103'; 'Rev. Fish Biol. Fish. 7 (1997) pp. 173'; 'Proceedings of the Sixth International Symposium on the Reproductive Physiology of Fish. John Grieg A/S, Bergen, Norway, 2000, pp. 211'). However, in recent years new data have emerged on the BPG axis in flatfish, especially at the level of the brain and pituitary. The evolutionarily advanced flatfishes are important model species both from an evolutionary point of view and also because many are candidates for aquaculture. The scope of this paper is to review the present status on the male teleost BPG axis, with an emphasis on flatfish. In doing so, we will first discuss the present understanding of the individual constituents of the axis in the best studied teleost models, and thereafter discuss available data on flatfish. Of the three constituents of the BPG axis, we will focus especially on the pituitary and gonadotropins. In addition to reviewing recent information on flatfish, we present some entirely new information on the phylogeny and molecular structure of teleost gonadotropins.

271 citations


"A systematic immunohistochemical su..." refers background in this paper

  • ...Instead, a direct axonal transport exists between hypothalamic neurons and pituitary endocrine cells via the hypophyseal stalk and the PN (Weltzien et al. 2004)....

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  • ...Thus, teleost fish represent interesting models for the study of pituitary ontogeny and phylogeny (for a review, see Weltzien et al. 2004)....

    [...]

  • ...However, the sexual cycle of salmonids differs from that of cychlid fish, such as tilapia, which are reproductive throughout the year (Baroiller and Guiguen 2001; Kawauchi et al. 1989; Melamed et al. 1998; Santos et al. 2001; Shimizu et al. 2003; Weltzien et al. 2004)....

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Journal ArticleDOI
TL;DR: It was found that proton permeability and substrate oxidation activity were greater in liver mitochondria from endotherms than those from ectotherms, and proton leak per milligram of inner membrane phospholipid correlated with 11 phospholIPid fatty acid compositional parameters, including unsaturation index.
Abstract: We measured the proton leak across the inner membrane of liver mitochondria isolated from six different vertebrate species and from obese and control Zucker rats. Proton leak at 37°C was similar in rat and pigeon, and in obese and control Zucker rats. Compared to rat, it was lower in cane toad, shingleback lizard, and the Madeiran lizard Lacerta dugessi. Proton leak at 20°C was similar in xenopus toad and higher in rainbow trout, compared to rat. In general, proton permeability and substrate oxidation activity were greater in liver mitochondria from endotherms than those from ectotherms. Analysis of this and previous data showed that proton leak per milligram of mitochondrial protein correlated with standard metabolic rate, and proton leak per milligram of inner membrane phospholipid correlated with 11 phospholipid fatty acid compositional parameters, including unsaturation index.

235 citations

Book
01 Jan 1974

209 citations


"A systematic immunohistochemical su..." refers result in this paper

  • ...…(O. niloticus) has revealed a structure and distribution pattern similar to those emerging when combining the results of other groups in various teleosts including tilapia (e.g. Holmes and Ball 1974; Leatherland et al. 1974; Joy and Sathyanesan 1980; Siegmund et al. 1987; Yan and Thomas 1991)....

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Frequently Asked Questions (1)
Q1. What are the contributions mentioned in the paper "A systematic immunohistochemical survey of the distribution patterns of gh, prolactin, somatolactin, ฀–tsh, ฀–fsh, ฀–lh, acth, and ฀–msh in the adenohypophysis of oreochromis niloticus , the nile tilapia" ?

Thus, the authors studied adjacent sections of the pituitary of Oreochromis niloticus, the tilapia, by conventional staining and immunohistochemistry with specific antisera directed against growth hormone ( GH ), prolactin ( PRL ), somatolactin ( SL ), thyrotropin ( beta-TSH ), follicle-stimulating hormone ( beta-FSH ), luteinising hormone ( beta-LH ), adrenocorticotropic hormone ( ACTH ) and melanocyte-stimulating hormone ( alphaMSH ). The authors present a complete map of the distinct localisation sites for the classical pituitary hormones, thereby providing a solid basis for future research on teleost pituitary.