Phosphatidylinositol 3-kinase in bovine lens and its stimulation by insulin and IGF-1.

Purpose: To identify and characterize phosphatidylinositol 3-kinase (PI-3K) in the lens and to study its involvement as a signal mediator in lens epithelial cells exposed to insulin and insulin-like growth factor (IGF)-1, which are known to induce lens epithelial cell proliferation and differentiation into fiber cells.

Methods: Concentric fiber cell layers from single bovine lens were prepared by dissolution in buffer. PI-3K activity in capsule-epithelium and fiber cell layers was determined after immunoprecipitation with antibodies against p85, the regulatory subunit of PI-3K.