title: Androgens and androgen receptor signaling contribute to ovarian development in the chicken embryo.
abstract: Androgens and androgen receptor (AR) signaling play important roles throughout development. In the chicken, AR signaling is involved in reproduction; however, its specific role is unclear. We show that AR signaling is involved in the normal development of the female embryonic gonads. The AR mRNA level was detected in male and female embryonic gonads by quantitative RT-PCR, and its expression was higher in females than in males at all developmental stages examined. In female embryos, the AR localized to nuclei of cells in the left gonad. Although AR expression was low in the majority of the medulla, high expression was detected in cells of lacunae within the medulla. In addition, AR expression increased in cells of cortical cords within the cortex with the progression of development. AR expression in the right gonad was lower than that in left gonad throughout development. In the male gonad, the AR localized to the cytoplasm of cells in seminiferous tubules at all stages. Female AR knockdown (ARKD) embryos infected with a retrovirus expressing micro RNAs targeting the AR showed normal asymmetric gonads (development of the left and depression of the right gonads), whereas the number of lacunae decreased. Furthermore, there was a disruption in the structure of cortical cords. By contrast, the gonads of ARKD males developed normally during embryogenesis. These results indicate that androgens and AR signaling are essential for the development of lacunae and cortical cords in gonads of female embryos.
authors.affiliation: Graduate School of Life Science, Hokkaido University, Kita 10 Nishi 8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan.
authors.forename: Ryoma
authors.initials: R
authors.lastname: Tanaka
authors.affiliation: Division of Reproductive and Developmental Biology, Department of Biological Sciences, Faculty of Science, Hokkaido University, Kita 10 Nishi 8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan.
authors.forename: Hiroe
authors.initials: H
authors.lastname: Izumi
authors.affiliation: Graduate School of Life Science, Hokkaido University, Kita 10 Nishi 8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan; Division of Reproductive and Developmental Biology, Department of Biological Sciences, Faculty of Science, Hokkaido University, Kita 10 Nishi 8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan. Electronic address: asatok@sci.hokudai.ac.jp.
authors.forename: Asato
authors.initials: A
authors.lastname: Kuroiwa
mesh_terms: D000728:Androgens / Q000378:metabolism*; D000818:Animals; D002642:Chick Embryo; D005260:Female; D018507:Gene Expression Regulation, Developmental; D055785:Gene Knockdown Techniques; D008297:Male; D010053:Ovary / Q000196:embryology* / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011944:Receptors, Androgen / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D000728:Androgens; D012333:RNA, Messenger; D011944:Receptors, Androgen
keywords: Cortical cords; Gonads; Knockdown; Lacuna; RNAi