Author
Shinji Adachi
Bio: Shinji Adachi is an academic researcher from National Institute for Basic Biology, Japan. The author has contributed to research in topics: Ovarian follicle & Gonadotropin. The author has an hindex of 17, co-authored 20 publications receiving 1386 citations.
Papers
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TL;DR: In this paper, the maturation-inducing activity of residues at various steps of purification was assessed by an in vitro germinal vesicle breakdown (GVBD) assay based on fully grown prophase-arrested folliculated oocytes of amago salmon.
253 citations
TL;DR: A two-cell-type model for the production of follicular estrogens, the thecal layer possibly contributing to estradiol-17β production by synthesizing androgens which are transferred to the granulosa layer and aromatized to est radiol- 17β is suggested.
217 citations
TL;DR: Results suggest that 17 alpha, 20 beta-diOHprog is the natural maturation-inducing steroid hormone common to three species of Salmoniformes, ayu, amago salmon, and rainbow trout, since supportive physiological and biochemical data are lacking.
146 citations
TL;DR: Diurnal maturation rhythm in the female red sea bream, Pagrus major, which spawns every day during the spawning season and has an asynchronous-type ovary containing oocytes at various stages of development, was studied by histological investigation of the ovary.
145 citations
TL;DR: A cDNA clone encoding cytochrome P‐450c17 (17α‐hydroxylase/17,20‐lyase) was isolated from a rainbow trout ovarian follicle cDNA library and shows a much greater homology with chicken P‐ 450c17 than with that of human, bovine and rat.
83 citations
Cited by
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TL;DR: The lability of sex-determination systems in fish makes some species sensitive to environmental pollutants capable of mimicking or disrupting sex hormone actions, and such observations provide important insight into potential impacts from endocrine disruptors, and can provide useful monitoring tools for impacts on aquatic environments.
2,283 citations
TL;DR: The likelihood that this ancient gene superfamily has existed for more than 3.5 billion years, and that the rate of P450 gene evolution appears to be quite nonlinear, is discussed.
Abstract: We provide here a list of 221 P450 genes and 12 putative pseudogenes that have been characterized as of December 14, 1992. These genes have been described in 31 eukaryotes (including 11 mammalian and 3 plant species) and 11 prokaryotes. Of 36 gene families so far described, 12 families exist in all mammals examined to date. These 12 families comprise 22 mammalian subfamilies, of which 17 and 15 have been mapped in the human and mouse genome, respectively. To date, each subfamily appears to represent a cluster of tightly linked genes. This revision supersedes the previous updates [Nebert et al., DNA 6, 1–11, 1987; Nebert et al., DNA 8, 1–13, 1989; Nebert et al., DNA Cell Biol. 10, 1–14 (1991)] in which a nomenclature system, based on divergent evolution of the superfamily, has been described. For the gene and cDNA, we recommend that the italicized root symbol "CYP" for human ("Cyp" for mouse), representing "cytochrome P450," be followed by an Arabic number denoting the family, a letter designating...
1,660 citations
TL;DR: This work proposes the adoption of a simple, universal terminology for the phases in the reproductive cycle, which can be applied to all male and female elasmobranch and teleost fishes, and includes immature, developing, spawning capable, regressing, and regenerating.
Abstract: As the number of fish reproduction studies has proliferated, so has the number of gonadal classification schemes and terms. This has made it difficult for both scientists and resource managers to communicate and for comparisons to be made among studies. We propose the adoption of a simple, universal terminology for the phases in the reproductive cycle, which can be applied to all male and female elasmobranch and teleost fishes. These phases were chosen because they define key milestones in the reproductive cycle; the phases include immature, developing, spawning capable, regressing, and regenerating. Although the temporal sequence of events during gamete development in each phase may vary among species, each phase has specific histological and physiological markers and is conceptually universal. The immature phase can occur only once. The developing phase signals entry into the gonadotropin-dependent stage of oogenesis and spermatogenesis and ultimately results in gonadal growth. The spawning cap...
846 citations
01 Nov 1994-Comparative Biochemistry and Physiology Part C: Pharmacology, Toxicology and Endocrinology
TL;DR: 11-Oxygenated androgens are generally more effective than T in stimulating secondary sexual characters, reproductive behaviour and spermatogenesis in teleost fishes but receptor-like binding has only reported for T and not for 11KT.
802 citations
TL;DR: The mechanisms that control oocyte growth are addressed in this review, albeit that the available information, as in all other vertebrates, is very limited.
Abstract: Oocyte growth and development is an important issue in fish and fisheries biology. This paper reviews the information available on oocyte growth patterns and the rates and dynamics of oocyte growth in teleosts. In synchronous spawners, the weight of the gonad may represent as much as 40% of the overall body weight of the fish. In asynchronous spawners, the weight of the mature ovary is considerably less than in synchronous ovulators, but the ovary shows a more regular periodicity and may grow repeatedly many times during the breeding season. There is a huge variability in egg size in teleosts, with the largest known measuring up to 8 cm in diameter. Within the limits of variance set by genetic constraints, egg size may vary between populations of the same species. Oocytes in all teleosts undergo the same basic pattern of growth: oogenesis, primary oocyte growth, cortical alveolus stage, vitellogenesis, maturation and ovulation. The mechanisms that control oocyte growth are addressed in this review, albeit that the available information, as in all other vertebrates, is very limited. The main hormones that have been shown to affect ovarian growth are gonadotrophin, thyroid hormones, growth hormone, insulin and insulin-like growth factors. An overview of the determinants of fecundity, with particular reference to oocyte recruitment and atresia, is the focus of the second part of the paper. Genetics and nutrition have major effects on fecundity, and studies so far suggest that the determinants of fecundity usually operate during the early part of gametogenesis. The role of atresia in determining fecundity is less clear. The final part of this review highlights some areas of study that are priorities for research on ovarian development in fish.
782 citations