Lipid interacting cytotoxins alter binding properties or epidermal growth factor (EGF) and tumor promoter (PDBu) receptors in rat pheochromocytoma (PC12) and human carcinoma (A431) cells: Philip Lazarovici and K.-F. Jesse Chan (Department of Neurobiology, The Weizmann Institute of Science, Rehovot, Israel, and Section of Neurotoxicology, LENP, NINCDS, NIH, Bethesda, MD 20892, U.S.A.)