Polyamines are involved in the control of cell cycle and cell-growth. In murine kidney, testosterone enhances gene expression of ornithine decarboxylase (ODC), the first enzyme in polyamine biosynthesis. In this study, we document the time-course effect of testosterone on 1- gene expression of ODC, antizyme (AZ1) and spermidine/spermine-N¹-acetyltransferase (N¹-SAT), 2- ODC activity in proximal convoluted tubules (PCT) and cortical proximal straight tubules (CPST) and 3- renal polyamine levels. Female mice were treated with testosterone for a period of 1, 2, 3 and 5 consecutive days. ODC gene expression was extremely low in kidneys of untreated female mice compared to that of males. Consequently, renal putrescine level was 7-fold lower in females than in males while spermidine and spermine levels did not differ between sexes. In female kidneys, testosterone treatment sharply increased ODC mRNA and protein levels as well as ODC activity. Testosterone increased the expression of ODC in PCT and CPST over different timecourses, which suggests that ODC activity is differentially regulated in distinct tubules. AZ1 and N¹-SAT mRNA expression was similar in male and female mouse kidneys. Testosterone treatment enhanced AZ1 and N¹-SAT mRNA levels in a time dependent manner by unknown molecular mechanisms. Putrescine and spermidine levels increased after testosterone treatment in female kidneys. Surprisingly, although ODC protein and activity were undetectable in female kidney, the levels of AZ1 mRNA and protein were similar to those of males. Therefore, one may propose that ODC protein could be continuously degraded by AZ1 in female kidneys.