Although no significant effects of acute binge alcohol on vertebral BMD or strength were observed, our results suggest that changes are occurring in bone at the molecular level in response to a 3-day alcohol binge. Approximately 1300 genes (over 10% of the genes passing quality control parameters) exhibited significant differential expression in the acute binge group (C1 vs. A1). Of the pathways affected by acute binge alcohol, the effects observed on the integrin-signaling pathway are discussed here based on the connection between integrin signaling and bone resorption. Integrins are transmembrane heterodimeric proteins consisting of α and β subunits that function by attaching cells to the extracellular matrix and transmitting matrix-derived signals to the interior of the cell. The αvβ3 integrin is the principal integrin expressed by osteoclasts (McHugh et al., 2000). We found that acute alcohol exposure modulated steady-state levels of a significant number of genes involved in integrin signaling, including a significant increase in mRNA levels of β3 integrin (Itgb3). Given the promiscuous nature of integrin heterodimer formation (Teitelbaum, 2005) an alcohol-related increase in β3 mRNA levels could increase
