title: Expression and function of class B scavenger receptor type I on both apical and basolateral sides of the plasma membrane of polarized testicular Sertoli cells of the rat.
abstract: Class B scavenger receptor type I (SR-BI), a multiligand membrane protein, exists in various organs and cell types. In the testis, SR-BI is expressed in two somatic cell types: Leydig cells and Sertoli cells. Unlike interstitially localized Leydig cells, Sertoli cells present within the seminiferous tubules keep contact with spermatogenic cells and form the tight junction to divide the seminiferous epithelium into the basal and adluminal compartments. In this study, the expression and function of SR-BI in rat Sertoli cells were examined with respect to dependency on the spermatogenic cycle, the plasma membrane polarity, and the pituitary hormone follicle-stimulating hormone (FSH). When the expression of SR-BI was histochemically examined with testis sections, both protein and mRNA were already present in Sertoli cells during the first-round spermatogenesis and continued to be detectable thereafter. The level of SR-BI mRNA expression in Sertoli cells was lower at spermatogenic stages I-VI than at other stages. SR-BI was present and functional (in mediating cellular incorporation of lipids of high density lipoprotein) at both the apical and basolateral surfaces of polarized Sertoli cells. Finally, SR-BI expression at both the protein and mRNA levels was stimulated by FSH in cultured Sertoli cells. These results indicate that SR-BI functions on both the apical and basolateral plasma membranes of Sertoli cells, and that SR-BI expression in Sertoli cells changes during the spermatogenic cycle and is stimulated, at least in cultures, by FSH.
authors.affiliation: Graduate School of Medical Science, Kanazawa University, Shizenken, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan.
authors.forename: Akihisa
authors.initials: A
authors.lastname: Nakagawa
authors.forename: Kaz
authors.initials: K
authors.lastname: Nagaosa
authors.forename: Tomoe
authors.initials: T
authors.lastname: Hirose
authors.forename: Kayoko
authors.initials: K
authors.lastname: Tsuda
authors.forename: Kunio
authors.initials: K
authors.lastname: Hasegawa
authors.forename: Akiko
authors.initials: A
authors.lastname: Shiratsuchi
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Nakanishi
mesh_terms: D000818:Animals; D018955:CD36 Antigens; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D016764:Cell Polarity; D002478:Cells, Cultured; D005640:Follicle Stimulating Hormone / Q000502:physiology; D005786:Gene Expression Regulation; D007985:Leydig Cells / Q000502:physiology; D008297:Male; D051381:Rats; D011971:Receptors, Immunologic / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D051116:Receptors, Scavenger; D051122:Scavenger Receptors, Class B; D012708:Sertoli Cells / Q000502:physiology*; D013091:Spermatogenesis; D013737:Testis / Q000166:cytology / Q000502:physiology; D019108:Tight Junctions / Q000378:metabolism
chemical_list: D018955:CD36 Antigens; D011971:Receptors, Immunologic; D051116:Receptors, Scavenger; C495125:Scarb1 protein, rat; D051122:Scavenger Receptors, Class B; D005640:Follicle Stimulating Hormone