title: Upregulation of P-glycoprotein activity in porcine oocytes and granulosa cells during in vitro maturation.
abstract: Multidrug resistance P-glycoprotein (Pgp), coded by the multidrug resistance type I (MDR1/ABCB1) gene, is an energy-dependent efflux pump and functions in systemic detoxification processes. In the present study, the expression and development of Pgp were evaluated in the porcine oocyte during in vitro maturation to compare with the expression of Pgp in cultured granulosa cells. As revealed by Western blotting using anti-human Pgp antibody, a single band of Pgp with an apparent molecular size of 170 kDa was detected in the germinal vesicle stage oocytes. The surface of GV oocyte was positively labeled by immunostaining. In the second metaphase oocyte after culture in the maturation medium containing porcine follicular fluid and human chorionic gonadotropin, the level of Pgp was increased. The elevation of the oocyte Pgp level was associated with increased activity of rhodamine 6G efflux from the oocyte, and its efflux was suppressed by verapamil, an inhibitor of Pgp. Removal of porcine follicular fluid from the maturation medium resulted in little alteration of the oocyte Pgp level. Expression of Pgp was also elevated in cultured porcine granulosa cells during cell maturation when stimulated with follicle-stimulating hormone or luteinizing hormone for 24-48 h. Collectively, the present results indicate that the transporting activity of P-glycoprotein upregulates in porcine oocytes and granulosa cells during exposure to gonadotropins or prior to ovulation.
authors.affiliation: Department of Animal and Marine Bioresource Sciences, Graduate School of Agriculture, Kyushu University, Fukuoka, Japan.
authors.forename: Kazuko
authors.initials: K
authors.lastname: Yokota
authors.forename: Takuro
authors.initials: T
authors.lastname: Hirano
authors.forename: Narumi
authors.initials: N
authors.lastname: Urata
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Yamauchi
authors.forename: Masa-aki
authors.initials: MA
authors.lastname: Hattori
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism*; D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002478:Cells, Cultured; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology; D015571:Follicular Fluid / Q000378:metabolism; D006107:Granulosa Cells / Q000187:drug effects / Q000378:metabolism*; D007986:Luteinizing Hormone / Q000494:pharmacology; D009865:Oocytes / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism*; D010060:Ovulation; D013552:Swine / Q000378:metabolism*; D015854:Up-Regulation; D014700:Verapamil / Q000494:pharmacology
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D002121:Calcium Channel Blockers; D006063:Chorionic Gonadotropin; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D014700:Verapamil