['To gain new insights into the molecular mechanisms of action of doxazosin, we investigated the prostatic stroma ultrastructure and the expression of genes involved with fibrosis, such as collagen type I and III (COL1A1 and COL3A1, respectively) and TGF-beta 1, in the rat ventral prostate.', 'Adult Wistar rats were treated with doxazosin (25mg/kg/day), and the ventral prostates were excised at 7 and 30days after treatment. Untreated rats were controls. Ventral prostates were subjected to ultrastructural, immunohistochemical, biochemical and molecular analyses.', 'Doxazosin-treated prostates showed thickened bundles of collagen fibrils, activated fibroblasts, enlarged neurotransmitter vesicles and increased tissue immunostaining for collagen type I and type III when compared to untreated prostates. After 7 and 30days of doxazosin treatment mRNA expression of COL1A1 and COL3A1 was significantly increased and reduced, respectively, compared to the control group. TGF-beta 1 mRNA and protein levels were increased after 7days of doxazosin treatment, whereas only mRNA levels remained increased after 30days of treatment.'] Is fibrosis-related gene expression in the prostate modulated by doxazosin treatment?