Background: Cell proliferation and turnover are fueled by stem cells.In a previous study, we demonstrated that rat eccrine sweat glands contained abundant bromodeoxyuridine (BrdU)-label retaining cells (LRCs).However, morphological observation showed that eccrine sweat glands usually showed little or no signs of homeostatic change.Objective: In this study, we account for why the homeostatic change is rare in eccrine sweat glands based on cytokinetic changes in BrdU-LRCs turnover, and we also determine the BrdU-labeled cell type.Methods: Thirty-six newborn SD rats, were intraperitoneally injected with 50 mg/kg BrdU twice daily at a 2 h interval for 4 consecutive days.After a chase period of 4, 6, 8, 12, 24 and 32 weeks, rats were euthanized,and the hind footpads were removed and processed for BrdU immunostaining, and BrdU/?-SMA and BrdU/CK14 double-immunostaining.BrdU-LRCs were observed in the ducts, secretory coils and mesenchymal cells in all survival time points.Results: The percentage of BrdU+ cells in rat eccrine sweat glands averaged 4.2?1.2 % after 4 weeks of chase, increased slightly by the 6th week, averaging 4.4?0.9 %, and peaked at 8 weeks, averaging 5.3?1.0 %.Subsequently, the average percentage of BrdU+ cells declined to 3.2?0.8 % by the 32nd week.There was no difference in the percentage of BrdU-LRCs among the different survival time points except that there is a significant decrease in the percentage of BrdU-LRCs detected at 24 weeks versus 8 weeks, and 32 weeks versus 8 weeks.Conclusions: The BrdU-LRCs turnover is slow in eccrine sweat glands, which account for why there are little or no signs of homeostatic change in eccrine sweat glands.