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Kikuyama S, Okada R, Hasunuma I, Nakada T. Some aspects of the hypothalamic and pituitary development, metamorphosis, and reproductive behavior as studied in amphibians. Gen Comp Endocrinol 2019; 284:113212. [PMID: 31238076 DOI: 10.1016/j.ygcen.2019.113212] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Revised: 06/12/2019] [Accepted: 06/21/2019] [Indexed: 01/10/2023]
Abstract
In this review article, information about the development of the hypothalamo-hypophyseal axis, endocrine control of metamorphosis, and hormonal and pheromonal involvements in reproductive behavior in some amphibian species is assembled from the works conducted mainly by our research group. The hypothalamic and pituitary development was studied using Bufo embryos and larvae. The primordium of the epithelial hypophysis originates at the anterior neural ridge and migrates underneath the brain to form a Rathke's pouch-like structure. The hypothalamo-hypophyseal axis develops under the influence of thyroid hormone (TH). For the morphological and functional development of the median eminence, which is a key structure in the transport of regulatory hormones to the pituitary, contact of the adenohypophysis with the undeveloped median eminence is necessary. For the development of proopiomelanocortin-producing cells, contact of the pituitary primordium with the infundibulum is required. The significance of avascularization in terms of the function of the intermediate lobe of the pituitary was evidenced with transgenic Xenopus frogs expressing a vascular endothelial growth factor in melanotropes. Metamorphosis progresses via the interaction of TH, adrenal corticosteroids, and prolactin (PRL). We emphasize that PRL has a dual role: modulation of the speed of metamorphic changes and functional development of organs for adult life. A brief description about a novel type of PRL (1B) that was detected was made. A possible reason why the main hypothalamic factor that stimulates the release of thyrotropin is not thyrotropin-releasing hormone, but corticotropin-releasing factor is considered in light of the fact that amphibians are poikilotherms. As regards the reproductive behavior in amphibians, studies were focused on the courtship behavior of the newt, Cynops pyrrhogaster. Male newts exhibit a unique courtship behavior toward sexually developed conspecific females. Hormonal interactions eliciting this behavior and hormonal control of the courtship pheromone secretion are discussed on the basis of our experimental results.
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Affiliation(s)
- Sakae Kikuyama
- Department of Biology, Faculty of Education and Integrated Sciences, Center for Advanced Biomedical Sciences, Waseda University, Tokyo 162-8480, Japan.
| | - Reiko Okada
- Department of Biological Science, Faculty of Science, Shizuoka University, Shizuoka 422-8529, Japan.
| | - Itaru Hasunuma
- Department of Biology, Faculty of Science, Toho University, Chiba 274-8510, Japan
| | - Tomoaki Nakada
- Department of Comparative and Behavioral Medicine, Nippon Veterinary and Life Science University, Tokyo 180-8602, Japan
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Van Bocxlaer I, Maex M, Treer D, Janssenswillen S, Janssens R, Vandebergh W, Proost P, Bossuyt F. Beyond sodefrin: evidence for a multi-component pheromone system in the model newt Cynops pyrrhogaster (Salamandridae). Sci Rep 2016; 6:21880. [PMID: 26935790 PMCID: PMC4776240 DOI: 10.1038/srep21880] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 01/18/2016] [Indexed: 11/09/2022] Open
Abstract
Sodefrin, a decapeptide isolated from the male dorsal gland of the Japanese fire belly newt Cynops pyrrhogaster, was the first peptide pheromone identified from a vertebrate. The fire belly salamander and sodefrin have become a model for sex pheromone investigation in aquatically courting salamanders ever since. Subsequent studies in other salamanders identified SPF protein courtship pheromones of around 20 kDa belonging to the same gene-family. Although transcripts of these proteins could be PCR-amplified in Cynops, it is currently unknown whether they effectively use full-length SPF pheromones next to sodefrin. Here we combined transcriptomics, proteomics and phylogenetics to investigate SPF pheromone use in Cynops pyrrhogaster. Our data show that not sodefrin transcripts, but multiple SPF transcripts make up the majority of the expression profile in the dorsal gland of this newt. Proteome analyses of water in which a male has been courting confirm that this protein blend is effectively secreted and tail-fanned to the female. By combining phylogenetics and expression data, we show that independent evolutionary lineages of these SPF’s were already expressed in ancestral Cynops species before the origin of sodefrin. Extant Cynops species continue to use this multi-component pheromone system, consisting of various proteins in addition to a lineage-specific peptide.
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Affiliation(s)
- Ines Van Bocxlaer
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050 Brussels, Belgium
| | - Margo Maex
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050 Brussels, Belgium
| | - Dag Treer
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050 Brussels, Belgium
| | - Sunita Janssenswillen
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050 Brussels, Belgium
| | - Rik Janssens
- Laboratory of Molecular Immunology, Department of Microbiology and Immunology, KU Leuven - University of Leuven, Minderbroedersstraat 10 - box 1030, B-3000 Leuven, Belgium
| | - Wim Vandebergh
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050 Brussels, Belgium
| | - Paul Proost
- Laboratory of Molecular Immunology, Department of Microbiology and Immunology, KU Leuven - University of Leuven, Minderbroedersstraat 10 - box 1030, B-3000 Leuven, Belgium
| | - Franky Bossuyt
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050 Brussels, Belgium
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Artur O, Wiesław B, Paweł G, Jacek M S. Multiple sex pheromone genes are expressed in the abdominal glands of the smooth newt (Lissotriton vulgaris) and Montandon's Newt (L. montandoni) (Salamandridae). Zoolog Sci 2008; 25:587-92. [PMID: 18624569 DOI: 10.2108/zsj.25.587] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2007] [Accepted: 04/03/2008] [Indexed: 11/17/2022]
Abstract
The smooth newt (Lissotriton "Triturus" vulgaris) and Montandon's newt (L."T." montandoni) are sister species exhibiting pronounced differences in male secondary sexual traits but nevertheless hybridizing and producing fertile hybrids in nature. Since pheromonal communication is an important aspect of the reproductive biology of urodeles, structural differentiation of peptide pheromones and their receptors may contribute to incipient reproductive isolation. The aim of the study was the identification of genes encoding putative courtship pheromone precursors in two newt species and the reconstruction of phylogenetic relationships among them. Our analyses were based on cDNA obtained from the transcripts from the abdominal glands of male newts. We identified five unique cDNA sequences encoding the putative pheromone precursors in L. vulgaris and three additional unique sequences in L. montandoni. The results indicate that in the abdominal glands of Lissotriton newts more than one pheromone-encoding gene is expressed and that these loci form a gene family. Phylogenetic analysis indicates that the divergence of at least some of these genes predates the radiation of European newts.
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Affiliation(s)
- Osikowski Artur
- Department of Comparative Anatomy, Institute of Zoology, Jagiellonian University, Kraków, Poland.
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