Tributyltin (TBT), a member of the organotin family, is a known endocrine 
disruptor. It persists long in the environment and is widely used in various 
industrial applications. This study was planned to understand its toxic 
influence on Leydig cells isolated from 28 day old wistar rats. In-vitro 
exposure to TBT-Chloride (TBTC) (300-3000 nM) reduced cell viability (DNA 
fragmentation, nuclear condensation and MTT assay) and affected testosterone 
production. TBTC induced both apoptotic and necrotic cell death (AnnexinV/PI 
binding assay). Involvement of calcium (Ca(2+)), redox imbalance (ROS, GSH and 
TBARS) and mitochondria in TBTC toxicity was evaluated by using Ca(2+) 
inhibitors (BAPTA-AM, EGTA, Ruthenium Red), free radical scavengers (NAC, 
C-Phycocyanin) and mitochondrial permeability transition pore inhibitor 
(Cyclosporine A). Protein expression analysis of phosphorylated MAPKinases 
(ERK1/2, JNK1/2, & p38), steroidogenic proteins (3β-HSD, StAR & TSPO) and 
apoptotic proteins (Bax, Bcl2) illustrates the cytotoxic and anti-steroidogenic 
activity of TBTC.