| Title: | Early embryonic modification of maternal hormones differs systematically among embryos of different laying order: A study in birds |
| Author(s): | Kumar N; van Faassen M; Kema I; Gahr M; Groothuis TGG; |
| Address: | "Behavioural Biology, Groningen Institute for Evolutionary Life Sciences, University of Groningen, the Netherlands; Behavioural Neurobiology, Max Planck Institute for Ornithology, Seewiesen, Germany. Electronic address: neeraj.bioscience@gmail.com. Laboratory Medicine, University Medical Center Groningen, University of Groningen, the Netherlands. Behavioural Neurobiology, Max Planck Institute for Ornithology, Seewiesen, Germany. Behavioural Biology, Groningen Institute for Evolutionary Life Sciences, University of Groningen, the Netherlands" |
| DOI: | 10.1016/j.ygcen.2018.08.014 |
| ISSN/ISBN: | 1095-6840 (Electronic) 0016-6480 (Linking) |
| Abstract: | "Vertebrate embryos are exposed to maternal hormones that can profoundly affect their later phenotype. Although it is known that the embryo can metabolize these maternal hormones, the metabolic outcomes, their quantitative dynamics and timing are poorly understood. Moreover, it is unknown whether embryos can adjust their metabolic activity to, for example, hormones or other maternal signals. We studied the dynamics of maternal steroids in fertilized and unfertilized rock pigeon eggs during early incubation. Embryos of this species are naturally exposed to different amounts of maternal steroids in the egg according to their laying position, which provides a natural context to study differential embryonic regulation of the maternal signals. We used mass spectrometric analyses to map changes in the androgen and estrogen pathways of conversion. We show that the active hormones are heavily metabolized only in fertilized eggs, with a corresponding increase in supposedly less potent metabolites already within one-fourth of total incubation period. Interestingly, the rate of androgen metabolism was different between embryos in different laying positions. The results also warrant a re-interpretation of the timing of hormone mediated maternal effects and the role of the supposedly biologically inactive metabolites. Furthermore, the results also provide a potential solution as to how the embryo can prevent maternal steroids in the egg from interfering with its sexual differentiation processes as we show that the embryo can metabolize most of the maternal steroids before sexual differentiation starts" |
| Keywords: | "Animals Columbidae/*metabolism Embryo, Nonmammalian/*metabolism Female Hormones/*metabolism Mating Factor Oviposition/*physiology Ovum/metabolism Steroids/metabolism Androgen conversion Birds Estrogens Hormone mediated maternal effects Progestagens Yolk h;" |
| Notes: | "MedlineKumar, Neeraj van Faassen, Martijn Kema, Ido Gahr, Manfred Groothuis, Ton G G eng Research Support, Non-U.S. Gov't 2018/08/16 Gen Comp Endocrinol. 2018 Dec 1; 269:53-59. doi: 10.1016/j.ygcen.2018.08.014. Epub 2018 Aug 12" |
