Abstract： Objective To investigate the role of PI3K/Akt signal pathway in albumin-induced transforming growth factor beta 1 (TGF-β1) expression and proliferation in renal proximal tubule cells (HK-2).Methods HK-2 cells were cultured in vitro and allocated to three groups: control, albumin(BSA) and BSA+ Ly294002 (PI3K/Akt specific inhibitor).Cell proliferation was assessed by MTT method.TGF-β1 mRNA expression was determined by RT-PCR and protein outputs from TGF-β1, phosphorylated PI3K (p-PI3K) and Akt (p-Akt) was measured by Western blotting at 12, 24 and 48 h of culture.Results MTT revealed that higher dosage of BSA (30 mg/ml) overload induced significant proliferation in HK-2 cells (P< 0.05).Compared with control group, remarkable increase or up-regnlation was shown in expression of TGF-β 1 mRNA (0.472±0.025 vs 0.233±0.021, P<0.05), protein output from TGF-β1 (296±20.1 vs 100±13.2, P<0.05), p-PI3K (P<0.05) and p-Akt (P<0.05), with BSA induction at 12.Addition of Ly294002 was demonstrated to inhibit HK-2 proliferation at 12 hours and protein expressions in TGF-β1, p-PI3K and p-Akt at 48 h (P<0.05).Conclusion Albumin may induce TGF-β1 production through the activation of PI3-K/Akt signal pathway in renal tubular epithelial cells.