FSH-, LH-, and TSH-expressing cells during development of Sparus aurata L. (Teleostei). An immunocytochemical study

Ayala, Alfonsa Garcı́a; Villaplana, M.; Hernández, M. P. García; Chaves-Pozo, Elena; Agulleiro, B.

doi:10.1016/s0016-6480(03)00198-9

Cited by 42 publications

(19 citation statements)

References 43 publications

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“…In mammals, it was demonstrated that FSH and LH are expressed by the same pituitary gonadotropic cells [34, 35]. In contrast, studies in teleosts by immunocytochemistry and in situ hybridization suggested, as in our study, that LHβ and FSHβ are expressed by separate cells: in salmonids [36,37,38], tuna [39], tilapia [6, 40], gilthead sea bream [41] and halibut [42]. The expression of LHβ and FSHβ by the same cells, as in mammals, or by separate cells, as in teleosts, is an important evolutionary divergence, with potential implications for the regulatory mechanisms of the two gonadotropins.…”

Section: Discussioncontrasting

confidence: 48%

Differential Regulation of Luteinizing Hormone and Follicle-Stimulating Hormone Expression during Ovarian Development and under Sexual Steroid Feedback in the European Eel

Schmitz

Aroua²,

Vidal³

et al. 2005

Neuroendocrinology

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Pituitary gonadotropins, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) are, in teleosts as in mammals, under the control of hypothalamic factors and steroid feedbacks. In teleosts, feedback regulations largely vary depending on species and physiological stage. In the present study the regulation of FSH and LH expression was investigated in the European eel, a fish of biological and phylogenetical interest as a representative of an early group of teleosts. The eel FSHβ subunit was cloned, sequenced and together with earlier isolated eel LHβ and glycoprotein hormone α (GPα) subunits used to study the differential regulation of LH and FSH. In situ hybridization indicated that FSHβ and LHβ are expressed by separate cells of the proximal pars distalis of the adenohypophysis, differently from the situation in mammals. The profiles of LHβ and FSHβ subunit expression were compared during experimental ovarian maturation, using dot-blot assays. Expression levels for LHβ and GPα increased throughout ovarian development with a positive correlation between these two subunits. Conversely, FSHβ mRNA levels decreased. To understand the role of sex steroids in these opposite variations, immature eels were treated with estradiol (E₂)and testosterone (T), both steroids being produced in eel ovaries during gonadal development. E₂ treatment induced increases in both LHβ and GPα mRNA levels, without any significant effect on FSHβ. In contrast, T treatment induced a decrease in FSHβ mRNA levels, without any significant effect on the other subunits. These data demonstrate that steroids exert a differential feedback on eel gonadotropin expression, with an E₂-specific positive feedback on LH and a T-specific negative feedback on FSH, leading to an opposite regulation of LH and FSH during ovarian development.

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Section: Discussioncontrasting

confidence: 48%

Differential Regulation of Luteinizing Hormone and Follicle-Stimulating Hormone Expression during Ovarian Development and under Sexual Steroid Feedback in the European Eel

Schmitz

Aroua²,

Vidal³

et al. 2005

Neuroendocrinology

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“…However, it is still unclear whether the FSH␤ and LH␤ are synthesized in the same cells as it occurs in tetrapods (Saito et al, 2002). The existence of distinct FSH␤ and LH␤ secreting gonadotropes has been reported in several fish species, such as Atlantic salmon and rainbow trout (Nozaki et al, 1990), bluefin tuna (Kagawa et al, 1998), killifish (Calman et al, 2001), gilthead seabream (García-Ayala et al, 2003), grouper (Li et al, 2005), and Senegalese sole (Cerdà et al, 2008). On the other hand, in platyfish (Magliulo-Cepriano et al, 1994) and Mediterranean yellowtail (García-Hernández et al, 2002), FSH␤ and LH␤ cells were equally distributed throughout the whole PPD.…”

Section: Discussionmentioning

confidence: 99%

Molecular characterization of Chinese sturgeon gonadotropins and cellular distribution in pituitaries of mature and immature individuals

Cao

Zhou

Zhang

et al. 2009

Molecular and Cellular Endocrinology

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“…During development, the neurohypophysisinterdigitates with the adenohypophysis, which on its part can be subdivided into (1) the pars distalis (PD), which can further be divided into the rostral pars distalis (RPD) and the proximal pars distalis (PPD) and (2) the pars intermedia (PI; for further details, see Figure 1). Multiple studies have documented the principal distribution of adenohypophyseal cells in fish [61, 65–68] and amphibians [69–71]; the impact of thyroid-disrupting chemicals, however, has not been investigated so far. …”

Section: Introductionmentioning

confidence: 99%

Alterations along the Hypothalamic-Pituitary-Thyroid Axis of the Zebrafish (Danio rerio) after Exposure to Propylthiouracil

Schmidt

Braunbeck

2011

Journal of Thyroid Research

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In the past, various approaches have been developed to detect adverse effects of pollutants on the thyroid of vertebrates, most of these with special emphasis on the South African clawed frog, Xenopus laevis. Although fish are primarily affected by thyroid-disrupting chemicals, studies into alterations of the thyroid of fish are scarce. Therefore, effects of the reference compound propylthiouracil on histopathology of the thyroid axis were analyzed in a modified early life-stage test with zebrafish (Danio rerio) exposed to propylthiouracil. The test substance induced dose-dependent alterations of thyroidal tissue concomitant with increases in the number of surrounding blood vessels. Despite this massive proliferation of the thyroid, zebrafish were not able to maintain thyroxin concentrations. The pituitary was affected displaying significant alterations in thyroid-stimulating hormone cell counts. Quantitative evaluation of pituitary surface areas revealed a dose-dependent increase of adenohypophyseal tissue. Distinct histopathological effects may contribute to a more easy identification and interpretation of alterations induced by thyroid-disrupting chemicals.

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FSH-, LH-, and TSH-expressing cells during development of Sparus aurata L. (Teleostei). An immunocytochemical study

Cited by 42 publications

References 43 publications

Differential Regulation of Luteinizing Hormone and Follicle-Stimulating Hormone Expression during Ovarian Development and under Sexual Steroid Feedback in the European Eel

Differential Regulation of Luteinizing Hormone and Follicle-Stimulating Hormone Expression during Ovarian Development and under Sexual Steroid Feedback in the European Eel

Molecular characterization of Chinese sturgeon gonadotropins and cellular distribution in pituitaries of mature and immature individuals

Alterations along the Hypothalamic-Pituitary-Thyroid Axis of the Zebrafish (Danio rerio) after Exposure to Propylthiouracil

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