Abstract: Objective To investigate the expressions of Cdc25A,cyclin B1 and androgen receptor (AR) by administering with combination regimen of low-dose gossypol acetic acid(GA) with steroid hormones ［desogestrel/ethinylestradiol/testosterone undecanote(DSG/E/TU)］ in adult rat testis． Methods Adult male rats were randomly divided into four groups．Group GH:rats were fed orally with GA［12.5mg/(kgI>&#/I>8226;day)］ and DSG［125μg/(kgI>&#/I>8226;day)］/E［25μg/(kgI>&#/I>8226;day)］/TU［100mg/(kgI>&#/I>8226;day)］;Group G:rats were administered with a single dose of GA［12.5mg/(kgI>&#/I>8226;day)］;Group H:DSG［125μg/(kgI>&#/I>8226;day)］/E［25μg/(kgI>&#/I>8226;day)］/TU［100mg/(kgI>&#/I>8226;day)］were administered to rats;Group C:rats only received vehicle(1% methyl cellulose)．The testes were excised at the 6th，8th and 10th week, respectively.The expressions of Cdc25A,cyclin B1 and AR are detected by immunohistochemical staining and Western blotting． Results Compared with the control group, the intensities of Cdc25A immunohistochemical positive staining were decreased in Leydig cells and acrosomes at the 6th，8th and 10th week(EM>P/EM><0.05), and increased in spermatocytes in G，H and GH group at the 6th and 8th week (EM>P/EM><0.05). The intensities of cyclin B1 immunohistochemical positive staining were decreased in Leydig cells in H and GH group at the 6th，8th and 10th week(EM>P/EM><0.05). AR positive staining appeared in the nuclei of Leydig cells in H and GH group instead of the cytoplasm. Western blotting showed that the expre

Key words: Gossypol, Steroid hormone, Cdc25A, Cyclin B1, Androgen receptor, Germ, Immunohistochemistry, Western blotting, Rat