<i>In vitro</i>Induction of Luteinizing Hormone Synthesis by Estrogen in Organ-Cultured Pituitary Glands of the Japanese Eel, Anguilla japonica

Saito, Koji; Chida, Yuka; Adachi, Souichi; Yamauchi, Kazuyo

doi:10.2108/zsj.20.69

Cited by 5 publications

(5 citation statements)

References 18 publications

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“…A previously established primary tissue culture system developed for zebrafish ( Danio rerio ) ( 32 ) was used, which is also similar to the system developed for Japanese eel ( Anguilla japonica ) pituitaries ( 33 ), except that we used an agar cylinder instead of elder pith as support for pituitary tissue. For salmon pituitary incubations, the temperature was set at 14-16°C.…”

Section: Methodsmentioning

confidence: 99%

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Pituitary Gonadotropin Gene Expression During Induced Onset of Postsmolt Maturation in Male Atlantic Salmon: In Vivo and Tissue Culture Studies

et al. 2022

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Precocious male maturation causes reduced welfare and increased production costs in Atlantic salmon (Salmo salar) aquaculture. The pituitary produces and releases follicle-stimulating hormone (Fsh), the gonadotropin triggering puberty in male salmonids. However, little is known about how Fsh production is regulated in Atlantic salmon. We examined, in vivo and ex vivo, transcriptional changes of gonadotropin-related genes accompanying the initial steps of testis maturation, in pituitaries of males exposed to photoperiod and temperature conditions promoting maturation (constant light and 16°C). Pituitary fshb, lhb and gnrhr2bba transcripts increased in vivo in maturing males (gonado-somatic index > 0.1%). RNA sequencing (RNAseq) analysis using pituitaries from genetically similar males carrying the same genetic predisposition to mature, but differing by responding or not responding to stimulatory environmental conditions, revealed 144 differentially expressed genes, ~2/3rds being up-regulated in responders, including fshb and other pituitary hormones, steroid-related and other puberty-associated transcripts. Functional enrichment analyses confirmed gene involvement in hormone/steroid production and gonad development. In ex vivo studies, whole pituitaries were exposed to a selection of hormones and growth factors. Gonadotropin-releasing hormone (Gnrh), 17β-estradiol (E2) and 11-ketotestosterone (11-KT) up-regulated gnrhr2bba and lhb, while fshb was up-regulated by Gnrh but down-regulated by 11-KT in pituitaries from immature males. Also pituitaries from maturing males responded to Gnrh and sex steroids by increased gnrhr2bba and lhb transcript levels, but fshb expression remained unchanged. Growth factors (inhibin A, activin A and insulin-like growth factor 1) did not change gnrhr2bba, lhb or fshb transcript levels in pituitaries either from immature or maturing males. Additional pituitary ex vivo studies on candidates identified by RNAseq showed that these transcripts were preferentially regulated by Gnrh and sex steroids, but not by growth factors, and that Gnrh/sex steroids were less effective when incubating pituitaries from maturing males. Our results suggest that a yet to be characterized mechanism up-regulating fshb expression in the salmon pituitary is activated in response to stimulatory environmental conditions prior to morphological signs of testis maturation, and that the transcriptional program associated with this mechanism becomes unresponsive or less responsive to most stimulators ex vivo once males had entered pubertal developmental in vivo.

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Section: Methodsmentioning

confidence: 99%

“…After the incubation period, pituitaries were collected for gene expression analyses. E 2 and 11-KT were purchased from Sigma-Aldrich and used at a final concentration of 100 ng/mL ( 33 ) and 100 nM ( 34 ), respectively. Gnrh salmon analog [1 µM ( 8 )] was purchased from Syndel.…”

Section: Methodsmentioning

confidence: 99%

Pituitary Gonadotropin Gene Expression During Induced Onset of Postsmolt Maturation in Male Atlantic Salmon: In Vivo and Tissue Culture Studies

et al. 2022

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“…Immunohistochemistry was performed as in a previous study 23 . In brief, pituitary glands were fixed in Bouin–Hollande sublimate, dehydrated through a series of ethanols, and embedded in paraffin.…”

Section: Methodsmentioning

confidence: 99%

“…Immunohistochemistry was performed as in a previous study. 23 In brief, pituitary glands were fixed in Bouin-Hollande sublimate, dehydrated through a series of ethanols, and embedded in paraffin. The embedded pituitary glands were cut sagittally at 4-mm thickness and sections were stained immu- nohistochemically with antibodies against pituitary hormones described above.…”

Section: Immunohistochemistrymentioning

confidence: 99%

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Immunohistochemical changes in production of pituitary hormones during artificial maturation of female Japanese eel Anguilla japonica

et al. 2007

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Specific antibodies against follicle-stimulating hormone b subunit (FSHb), prolactin (PRL), and somatolactin (SL) of the Japanese eel Anguilla japonica were produced. These antibodies, as well as antibodies against luteinizing hormone b subunit (LHb) and growth hormone (GH) produced previously, were used to examine changes in the production of pituitary hormones in female eels during maturation induced by salmon pituitary homogenate (SPH) injection. Immunohistochemical observations showed a decrease in FSH production after SPH injection, suggesting that SPH inhibits FSH production. In contrast, LH production increased markedly with maturation. The number of GH producing cells decreased gradually during maturation, possibly because of inhibition by exogenous GH present in the SPH and/or endogenous insulin-like growth factor-I produced by the stimulation of salmon GH. Although changes in the number of PRL producing cells with maturation were not evident, the number of SL producing cells showed a peak at the late vitellogenic stages, and thereafter decreased to the migratory nucleus stage. These results suggest that GH and SL are involved in sexual maturation in SPH injected eels, as in other fishes.

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The Gonadoliberin(S)-Gonadotropin(S) Axis in the Eel: Expression and Regulation Under Induced Maturation and Sex Steroid Feedbacks

Aroua¹,

Rousseau²,

Schmitz

et al. 2009

Spawning Migration of the European Eel

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In vitroInduction of Luteinizing Hormone Synthesis by Estrogen in Organ-Cultured Pituitary Glands of the Japanese Eel, Anguilla japonica

Cited by 5 publications

References 18 publications

Pituitary Gonadotropin Gene Expression During Induced Onset of Postsmolt Maturation in Male Atlantic Salmon: In Vivo and Tissue Culture Studies

Pituitary Gonadotropin Gene Expression During Induced Onset of Postsmolt Maturation in Male Atlantic Salmon: In Vivo and Tissue Culture Studies

Immunohistochemical changes in production of pituitary hormones during artificial maturation of female Japanese eel Anguilla japonica

The Gonadoliberin(S)-Gonadotropin(S) Axis in the Eel: Expression and Regulation Under Induced Maturation and Sex Steroid Feedbacks

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