Aim:To evaluate the testosterone mimetic properties of icariin.Methods:Forty-eight healthy male Sprague-Dawleyrats at the age of 15 months were randomly divided into four groups with 12 rats each:the control group(C),the modelgroup(M),the icariin group(ICA)and the testosterone group(T).The reproductive system was damaged by cyclo-phosphamide(intraperitoneal injection,20 mg/kg-day)for 5 consecutive days for groups M,ICA and T,at the sixth day,ICA(gastric gavage,200 mg/kg·day)for the ICA group and sterandryl(subcutaneous injection,5 mg/rat.day)for the Tgroup for 7 consecutive days,respectively.The levels of serum testosterone,luteinizing hormone(LH),folliclestimulating hormone(FSH),serum bone Gla-protein(BGP)and tartrate-resistant acid phosphatase activity in serum(StrACP)were determined.The histological changes of the testis and the penis were observed by microscope withhematoxylin-eosin(HE)staining and terminal deoxynucleotidyl transferase biotin-dUTP-X nick end labeling(TUNEL),respectively.Results:(1)Icariin improved the condition of reproductive organs and increased the circulating levelsof testosterone.(2)Icariin treatment also improved the steady-state serum BGP and might have promoted boneformation.At the same time,it decreased the serum levels of StrACP and might have reduced the bone resorption.(3)Icarrin suppressed the extent of apoptosis of penile cavernosal smooth muscle cells.Conclusion:Icariin has test-osterone mimetic properties and has therapeutic potential in the management of hypoandrogenism.(Asian J Androl2006 Sep;8:601-605) Aim: To evaluate the testosterone mimetic properties of icariin.Methods:Forty-eight healthy male Sprague-Dawleyrats at the age of 15 months were randomly divided into four groups with 12 rats each:the control group(C),the modelgroup(M) ,the icariin group(ICA)and the testosterone group(T).The reproductive system was damaged by cyclo-phosphamide(intraperitoneal injection,20 mg/kg-day) for 5 consecutive days for groups M,ICA and T,at the sixth Day,ICA(gastric gavage,200 mg/kg·day)for the ICA group and sterandryl(subcutaneous injection,5 mg/rat.day)for the Tgroup for 7 consecutive days,respectively.The levels of serum testosterone,luteinizing hormone ( LH), folliclestimulating hormone (FSH), serum bone Gla-protein (BGP) and tartrate-resistant acid phosphatase activity in serum (StrACP) were determined. The histological changes of the testis and the penis were observed by microscope with hematoxylin-eosin (HE )staining and terminal deoxynucleotidyl transferase biotin-dUTP-X nick end labeling(TUNEL),respec tively.Results:(1)Icariin improved the condition of reproductive organs and increased the circulating levelsof testosterone.(2)Icariin treatment also improved the steady-state serum BGP and might have promoted boneformation.At the same time, it decreased the Of StrACP and might have reduced the bone resorption. (3)Icarrin suppressed the extent of apoptosis of penile cavernosal smooth muscle cells.Conclusion:Icariin has test-osterone mimetic properties and has therapeutic potential in the management of hypoandrogenism.(Asian J Androl2006 Sep ;8:601-605)