title: Areolae of the placenta in the Antarctic minke whale (Balaenoptera bonaerensis).
abstract: In this study, we examined the existence and structure of areolae and the steroidogenesis of areolar trophoblast cells in the Antarctic minke whale placenta morphologically and immunohistochemically. Placentas were collected from the 15th, 16th and 18th Japanese Whale Research Program under Special Permit in the Antarctic (JARPA) and 1st JARPA II organized by the Institute of Cetacean Research in Tokyo, Japan. The opening and cavity of fetal areolae formed by taller columnar trophoblast cells (areolar trophoblast cells) with long microvilli and a bright cytoplasm, as compared with the trophoblast cells of the chorionic villi interdigitating with the endometrial crypts, were recognized in observations of serial sections. The opening of the areolar cavity was hidden by chorionic villi with areolar trophoblast cells. Furthermore, a closed pouch-like structure lined by tall columnar cells similar to areolar trophoblast cells within the stroma of chorionic villi was noticed and continued to the areolar cavity, with the opening seen on serial sections. In a surface investigation of the chorion and endometrium by SEM, maternal (endometrial) areolae irregularly surrounded by endometrial folds were obvious. Moreover, we distinguished areolar trophoblast cells with long microvilli attached with many blebs from trophoblast cells. In our immunohistochemical observations, a steroidogenic enzyme, cytochrome P450 side chain cleavage enzyme (P450scc), was detected with strong immunoreactivity in trophoblast cells. However, areolar trophoblast cells showed weak or no immunoreactivity for P450scc.
authors.affiliation: Laboratory of Veterinary Anatomy, Department of Basic Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, Hokkaido 080-8555, Japan.
authors.forename: Motoki
authors.initials: M
authors.lastname: Sasaki
authors.forename: Yoko
authors.initials: Y
authors.lastname: Amano
authors.forename: Daisuke
authors.initials: D
authors.lastname: Hayakawa
authors.forename: Toshio
authors.initials: T
authors.lastname: Tsubota
authors.forename: Hajime
authors.initials: H
authors.lastname: Ishikawa
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Mogoe
authors.forename: Seiji
authors.initials: S
authors.lastname: Ohsumi
authors.forename: Masafumi
authors.initials: M
authors.lastname: Tetsuka
authors.forename: Akio
authors.initials: A
authors.lastname: Miyamoto
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Fukui
authors.forename: Teguh
authors.initials: T
authors.lastname: Budipitojo
authors.forename: Nobuo
authors.initials: N
authors.lastname: Kitamura
mesh_terms: D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D005260:Female; D050636:Minke Whale / Q000378:metabolism*; D010920:Placenta / Q000166:cytology* / Q000378:metabolism; D011247:Pregnancy; D014327:Trophoblasts / Q000166:cytology* / Q000378:metabolism
chemical_list: D003577:Cytochrome P-450 Enzyme System