title: Immunohistochemical evidence identifying the site of androgen production in the ovary of the protogynous grouper Epinephelus merra.
abstract: Androgen plays an important role in the developing ovaries of female fish. However, little is known regarding either the sites of production of androgen or its functional roles. In the present study, we investigated immunohistochemically the localization of cholesterol-side-chain-cleavage (P450scc) and cytochrome P45011beta-hydroxylase (P45011beta) with antibodies P450scc and P45011beta in the ovary of the female honeycomb grouper Epinephelus merra during its reproductive cycle. Clusters of strongly immunopositive cells, with 100-1000 cells in each cluster, against both P450scc and P45011beta, were observed throughout the annual reproductive cycle in tissue near blood vessels in the tunica ovary surrounding the outer periphery of the ovary. The ultrastructural characteristics of these cells showed that they were steroid-producing cells. In contrast, immunopositive cells against P450scc but not against P45011beta were localized in the theca layer surrounding the outer periphery of oocytes. These results suggest that two distinct steroid biosynthesis sites exist in the ovary and that cells at the two sites differ functionally. The only cells that biosynthesize 11-ketotestosterone are found in clusters in the vicinity of blood vessels; they possibly play a physiological role in oocyte growth and gonadal restructuring during the sex change of individuals of this species.
authors.affiliation: Sesoko Station, Tropical Biosphere Research Center, University of the Ryukyus, Motobu, Okinawa, Japan. k038333@eve.u-ryukyu.ac.jp
authors.forename: Mohammad Ashraful
authors.initials: MA
authors.lastname: Alam
authors.forename: Hiroki
authors.initials: H
authors.lastname: Komuro
authors.forename: Ramji Kumar
authors.initials: RK
authors.lastname: Bhandari
authors.forename: Shigeo
authors.initials: S
authors.lastname: Nakamura
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Soyano
authors.forename: Masaru
authors.initials: M
authors.lastname: Nakamura
mesh_terms: D000728:Androgens / Q000096:biosynthesis*; D000818:Animals; D015153:Blotting, Western; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D005260:Female; D007150:Immunohistochemistry; D006899:Mixed Function Oxygenases / Q000378:metabolism; D008954:Models, Biological; D010053:Ovary / Q000378:metabolism* / Q000648:ultrastructure; D010473:Perciformes / Q000033:anatomy & histology / Q000502:physiology*
chemical_list: D000728:Androgens; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; D002786:Cholesterol Side-Chain Cleavage Enzyme