L-744,832 inhibits H-Ras, but not N-Ras, farnesylation in vivo. Wild-type mice were injected with a single dose of either 40 mg/kg of 80 mg/kg of L-744,832, then killed 2, 4, 16, 24, or 48 hours after treatment. Mononuclear cells were isolated from hematopoietic tissues, lysed, immunoprecipitated, subject to gel electrophoresis, and blotted as described in Materials and Methods. Bands corresponding to unprocessed and processed Ras are labeled with open and closed arrows, respectively. Cells from untreated mice are labeled “U” and a lysate prepared from a compactin-treated cell line is labeled “C.” (A) Western blot probed with an H-Ras antibody. (B) The same Western blot was stripped and reprobed with an N-Ras antibody.