title: Seasonal changes in morphology and steroid receptor expression in the prostate of the brushtail possum (Trichosurus vulpecula): an animal model for the study of prostate growth?
abstract: The prostate of the brushtail possum undergoes growth and regression during the year. The present study investigated the morphological changes and expression of androgen and oestrogen receptors during the breeding and non-breeding seasons. Prostate tissue was collected from adult possums at 2-monthly intervals. The periurethral and outer glandular areas were separated and the volume of stromal, epithelial and luminal tissues measured in each area. Immunohistochemistry was used to investigate cell proliferation with proliferating cell nuclear antigen (PCNA) and to localise androgen receptor (AR) and oestrogen receptors α and β (ERα, ERβ). Seasonal changes in expression of the three receptors were investigated using quantitative PCR and western blot analysis. During the breeding season the volume of stromal tissue in the periurethral area and the luminal volume in the glandular area significantly increased. The change in periurethral volume was associated with increased PCNA-immunopositive cells. While the localisation of AR to the stromal and epithelial cells did not change, there was a significant increase in receptor expression before the main breeding season. ERα and ERβ expression and localisation did not alter during the year. Similarities in receptor expression and localisation suggest that the possum may be a suitable animal model for the study of human prostate growth.
authors.affiliation: Centre for Reproduction and Genomics, Department of Anatomy & Structural Biology, Otago School of Medical Sciences, University of Otago, PO Box 913, Dunedin, New Zealand.
authors.forename: Helen
authors.initials: H
authors.lastname: Martyn
authors.forename: Kamali
authors.initials: K
authors.lastname: Pugazhenthi
authors.forename: Maree
authors.initials: M
authors.lastname: Gould
authors.forename: Jo W
authors.initials: JW
authors.lastname: Fink
authors.forename: Bernie
authors.initials: B
authors.lastname: McLeod
authors.forename: Helen D
authors.initials: HD
authors.lastname: Nicholson
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D015153:Blotting, Western; D049109:Cell Proliferation; D004847:Epithelial Cells / Q000378:metabolism; D047628:Estrogen Receptor alpha / Q000378:metabolism; D047629:Estrogen Receptor beta / Q000378:metabolism; D007150:Immunohistochemistry; D008297:Male; D023421:Models, Animal; D009929:Organ Size; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D011467:Prostate / Q000254:growth & development / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D011944:Receptors, Androgen / Q000378:metabolism; D011987:Receptors, Steroid / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012621:Seasons; D012726:Sexual Behavior, Animal; D017154:Stromal Cells / Q000378:metabolism; D048330:Trichosurus / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*
chemical_list: D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D018809:Proliferating Cell Nuclear Antigen; D012333:RNA, Messenger; D011944:Receptors, Androgen; D011987:Receptors, Steroid