MORPHOLOGICAL OBSERVATION ON REVERSAL PROCESSES OF SEX-DIFFERENTIATION IN THE GENETIC FEMALE GONAD OF THE MEDAKA, ORYZIAS LATIPES, BY ANDROGEN
スポンサーリンク
概要
- 論文の詳細を見る
Newly hatched fry of the genetic female (X^rX^r) medaka (d-rR strain) were daily given a methyltestosterone diet (50μg/g) until they grew more than 13mm in body length. Using both a light- and electron-microscope, morphological changes in the gonad undergoing sex-reversal were studied with special reference to initial transition steps in the reversal of germ cells from genetic female towards the phenotypic male direction. Special attention was also paid to the degenerating processes of oocytes differentiated from germ cells prior to and during sex-reversal. The first appearance of male gonial cells in the female gonad was in about the 9-10mm stage, when most germ cells have already transformed through oogonia into enlarged perinucleolar oocytes. It is most likely that male gonial cells have differentiated from some of the female germ cells, each of which is enclosed within a thin layer of somatic cells to form a distinct acinus of spermatogonia. As these acini increased in number and expanded in dimension by inner gonial proliferation, a typical testicular structure of tubular cysts was formed. In inverse proportion to the progressive cystic (acinous) formation, oogenesis was greatly suppressed by exogeneous androgen. Consequently, oocytes previously differentiated were doomed to degeneration and finally transformed into complicated debris of large whorls or myelin-like structures displaying various abnormalities in form. These, together with spermatide debris degraded after spermiogenesis, were finally phagocytosed by thickened epithelial (Sertoli) cells lining the cysts, which were filled with many mature spermatozoa in 25-26mm body length stage when the gonad was established as a perfect testis. After oocyte degeneration, it was found that surrounding follicle (granulosa) cells gave evidence of much phagocytosis and suggested that they possibly play a principal role in the phagocytic exclusion of debris of degenerated oocytes.
著者
-
KOBAYASHI H.
Department of Mechanical Science and Bioengineering, School of Engineering Science, Osaka University
-
Hishida T.
Department Of Biology Asahi University School Of Liberal Arts
関連論文
- Spontaneous Bending of Ni-Ti Alloy Plates Caused by Preferential Hydrogen Absorption
- MORPHOLOGICAL OBSERVATION ON REVERSAL PROCESSES OF SEX-DIFFERENTIATION IN THE GENETIC FEMALE GONAD OF THE MEDAKA, ORYZIAS LATIPES, BY ANDROGEN
- The role of nuclear factor-kappa B in bacterial translocation in cholestatic rats
- α-Glutathione-s-transferase as a new sensitive marker of hepatocellular damage in biliary atresia
- P-122 A case of botryoid Wilms tumor
- Immunoadsorbent Plasmapheresis Using Dextran Sulfate Column for Lupus Nephritis(Collagen Disease,General Presentation,Proceedings of the Thirteenth Annual Meeting of Japanese Society for Apheresis)
- APPLICATION OF GRANULO-MONOCYTES APHERESIS BY G-1 COLUMN TO THE PATIENTS WITH RHEUMATOID ARTHRITIS
- A local feedback law for hyper-redundant manipulators
- Design and Optimization of Peptide-Based Vaccines for Cancer
- Study of Magnetic Phase Transitions in YVO_3 by Non-linear Susceptibility
- Interface States for Ultrathin Chemical Oxide Layers on Si(111) and Si(100)
- Alterations in Ultrastructural Localization of Growth-associated Protein-43 (GAP-43) in Periodontal Ruffini Endings of Rat Molars during Experimental Tooth Movement
- Effect of Continuous Hydrogen Charging on Tensile and Fatigue Properties of Amorphous Ni-Zr Alloy Membranes