title: The role of pituitary gonadotropins in gonadal sex differentiation in the protogynous Malabar grouper, Epinephelus malabaricus.
abstract: The aim of this study was to clarify the roles of 2 gonadotropins (GTHs), follicle-stimulating hormone (FSH) and luteinizing hormone (LH), on sex differentiation in the protogynous Malabar grouper, Epinephelus malabaricus. To do this, the mRNA expression patterns of GTH subunits (cga, fshb, and lhb) in the fish pituitary throughout gonadal sex differentiation were investigated. Real-time reverse transcriptase (RT)-PCR showed that cga and fshb were present in the undifferentiated and ovarian differentiation stages, and that the expression levels significantly increased after ovarian differentiation (AOD). However, lhb was not expressed before ovarian differentiation (BOD) and was first detected AOD. Next, to investigate the differentiation and distribution of Fshb and Lhb-producing cells in the pituitary of fish throughout gonadal sex differentiation, immunohistochemical analysis was used to detect teleost GTH subunits. Positive immunoreactivity against Fshb and Lhb was not detected in the pituitary BOD; Fshb and Lhb-positive cells first appeared in the pituitary AOD. It therefore seems unlikely that pituitary gonadotropins play a major role in the control of gonadal sex differentiation in the Malabar grouper.
authors: Sesoko Station, Tropical Biosphere Research Center, University of the Ryukyus, 3422 Sesoko, Motobu, Okinawa 905-0227, Japan. murata-r@aquas.or.jp
authors: Ryosuke
authors: R
authors: Murata
authors: Yasuhisa
authors: Y
authors: Kobayashi
authors: Hirofumi
authors: H
authors: Karimata
authors: Kazuo
authors: K
authors: Kishimoto
authors: Motofumi
authors: M
authors: Kimura
authors: Akio
authors: A
authors: Shimizu
authors: Masaru
authors: M
authors: Nakamura
mesh_terms: D000818:Animals; D001492:Bass / Q000235:genetics / Q000378:metabolism*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000235:genetics / Q000378:metabolism; D006065:Gonadotropins, Pituitary / Q000235:genetics / Q000378:metabolism*; D007150:Immunohistochemistry; D007986:Luteinizing Hormone / Q000235:genetics / Q000378:metabolism; D008297:Male; D010053:Ovary / Q000166:cytology / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D012733:Sex Differentiation / Q000235:genetics / Q000502:physiology*
chemical_list: D006065:Gonadotropins, Pituitary; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone