Effects of estradiol or testosterone treatment on expression of gonadotropin subunit mRNAs and proteins in the pituitary of juvenile brown hagfish, Paramyxine atami

Nozaki, Masumi; Uchida, Katsuhisa; Honda, Kazuo; Shimotani, Toyokazu; Nishiyama, Maki

doi:10.1016/j.ygcen.2013.04.034

Cited by 6 publications

(8 citation statements)

References 42 publications

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“…In addition, purified native GTH induced release of gonadal sex steroids (estradiol and testosterone) in vitro. Furthermore, tonic administration of estradiol resulted in significant accumulation of immunoreactivities of both a-and b-subunits of GTH in the pituitary of juvenile brown hagfish (Miki et al, 2006;Nozaki et al, 2013). These findings clearly suggested the presence of a GTH-gonad feedback system, similar to that of gnathostomes, in the hagfish.…”

Section: Introductionmentioning

confidence: 72%

Molecular cloning of cytochrome P450 side-chain cleavage and changes in its mRNA expression during gonadal development of brown hagfish, Paramyxine atami

Nishiyama

Uchida

Abe

et al. 2015

General and Comparative Endocrinology

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Section: Introductionmentioning

confidence: 72%

Molecular cloning of cytochrome P450 side-chain cleavage and changes in its mRNA expression during gonadal development of brown hagfish, Paramyxine atami

Nishiyama

Uchida

Abe

et al. 2015

General and Comparative Endocrinology

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“…On the other hand, testosterone treatment in the juvenile brown hagfish had no effect on the staining intensities of the ir-GTHα and ir-GTHβ in the pituitary (58). Nevertheless, testosterone treatment resulted in the suppression of mRNA expressions of both GTHα and GTHβ in the pituitary (58).…”

Section: Feedback Regulation Of Hagfish Gth Synthesis and Secretionmentioning

confidence: 93%

“…However, mRNA levels of GTHα and GTHβ in the pituitary were not, or only transiently, increased by the estradiol treatment (58). The latter results suggest that syntheses of both α- and β-subunits of GTH were not, or only transiently, affected by the estradiol treatment.…”

Section: Feedback Regulation Of Hagfish Gth Synthesis and Secretionmentioning

confidence: 99%

“…Estradiol treatment in the juvenile brown hagfish resulted in the marked accumulation of both immunoreactive (ir)-GTHα and ir-GTHβ in the pituitary (58). However, mRNA levels of GTHα and GTHβ in the pituitary were not, or only transiently, increased by the estradiol treatment (58).…”

Section: Feedback Regulation Of Hagfish Gth Synthesis and Secretionmentioning

confidence: 99%

“…Nevertheless, testosterone treatment resulted in the suppression of mRNA expressions of both GTHα and GTHβ in the pituitary (58). Therefore, testosterone probably acts to suppress both the synthesis and the secretion of GTH.…”

Section: Feedback Regulation Of Hagfish Gth Synthesis and Secretionmentioning

confidence: 99%

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Hypothalamic-Pituitary-Gonadal Endocrine System in the Hagfish

Nozaki

2013

Front. Endocrinol.

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The hypothalamic-pituitary system is considered to be a seminal event that emerged prior to or during the differentiation of the ancestral agnathans (jawless vertebrates). Hagfishes as one of the only two extant members of the class of agnathans are considered the most primitive vertebrates known, living or extinct. Accordingly, studies on their reproduction are important for understanding the evolution and phylogenetic aspects of the vertebrate reproductive endocrine system. In gnathostomes (jawed vertebrates), the hormones of the hypothalamus and pituitary have been extensively studied and shown to have well-defined roles in the control of reproduction. In hagfish, it was thought that they did not have the same neuroendocrine control of reproduction as gnathostomes, since it was not clear whether the hagfish pituitary gland contained tropic hormones of any kind. This review highlights the recent findings of the hypothalamic-pituitary-gonadal endocrine system in the hagfish. In contrast to gnathostomes that have two gonadotropins (GTH: luteinizing hormone and follicle-stimulating hormone), only one pituitary GTH has been identified in the hagfish. Immunohistochemical and functional studies confirmed that this hagfish GTH was significantly correlated with the developmental stages of the gonads and showed the presence of a steroid (estradiol) feedback system at the hypothalamic-pituitary levels. Moreover, while the identity of hypothalamic gonadotropin-releasing hormone (GnRH) has not been determined, immunoreactive (ir) GnRH has been shown in the hagfish brain including seasonal changes of ir-GnRH corresponding to gonadal reproductive stages. In addition, a hagfish PQRFamide peptide was identified and shown to stimulate the expression of hagfish GTHβ mRNA in the hagfish pituitary. These findings provide evidence that there are neuroendocrine-pituitary hormones that share common structure and functional features compared to later evolved vertebrates.

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Reproduction in agnathan fishes: Lampreys and hagfishes

Docker

2024

Hormones and Reproduction of Vertebrates, Volume 1

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Effects of estradiol or testosterone treatment on expression of gonadotropin subunit mRNAs and proteins in the pituitary of juvenile brown hagfish, Paramyxine atami

Cited by 6 publications

References 42 publications

Molecular cloning of cytochrome P450 side-chain cleavage and changes in its mRNA expression during gonadal development of brown hagfish, Paramyxine atami

Molecular cloning of cytochrome P450 side-chain cleavage and changes in its mRNA expression during gonadal development of brown hagfish, Paramyxine atami

Hypothalamic-Pituitary-Gonadal Endocrine System in the Hagfish

Reproduction in agnathan fishes: Lampreys and hagfishes

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