title: Apolipoprotein A-I production by chicken granulosa cells.
abstract: In avian species such as the chicken, development of the oocyte is associated with massive deposition of yolk in this cell. Oocytes grow within the follicle, a compartment consisting of a very specialized set of cells and acellular structures. The oocyte is surrounded by the perivitelline layer and granulosa cells, which are separated from the thecae by a pronounced basement membrane. In addition to the production of yolk precursors in the liver, we have long implied that cells within the follicle make a direct contribution to the growth of the oocyte. Here we show that chicken granulosa cells express and actively secrete apolipoprotein A-I (apoA-I) as a part of particles with very high density. The granulosa cell-derived, apoA-I-containing material is different from the small portion of yolk high density lipoprotein that arises via transfer from the peripheral circulation. We propose that the ApoA-I-containing particles secreted by granulosa cells 1) support the growth of the rapidly growing germ cell, possibly by direct lipid transfer to the plasma membrane of the oocyte, and/or 2) deliver cholesteryl esters to the steroid-producing cells of the theca layer. These findings are discussed with respect to the proposed functions of apoE (an apolipoprotein not found in chicken) within the mammalian follicle.
authors.affiliation: The Department of Molecular Genetics, Biocenter and University of Vienna, Austria.
authors.forename: M
authors.initials: M
authors.lastname: Hermann
authors.forename: K A
authors.initials: KA
authors.lastname: Lindstedt
authors.forename: R
authors.initials: R
authors.lastname: Foisner
authors.forename: S
authors.initials: S
authors.lastname: Mörwald
authors.forename: M G
authors.initials: MG
authors.lastname: Mahon
authors.forename: R
authors.initials: R
authors.lastname: Wandl
authors.forename: W J
authors.initials: WJ
authors.lastname: Schneider
authors.forename: J
authors.initials: J
authors.lastname: Nimpf
mesh_terms: D000818:Animals; D016632:Apolipoprotein A-I / Q000032:analysis / Q000096:biosynthesis*; D002645:Chickens; D005260:Female; D005455:Fluorescent Antibody Technique; D006107:Granulosa Cells / Q000166:cytology / Q000378:metabolism*; D009865:Oocytes / Q000166:cytology / Q000378:metabolism
chemical_list: D016632:Apolipoprotein A-I