Does clofibrate mobilize cholesterol from tissues?

Previous work by the authors (1) showed that in the high-lipid-fed rat, clofibrate (CPIB) lowered the deposition of cholesterol in the aorta and kidney. The possibility was raised that CPIB might mobilize cholesterol from these organs. This possibility was also raised by Tolman et al. (2) in their paper. Kritchevsky et al. (3) raised another possible explanation for the production of lower tissue cholesterol levels produced by CPIB when they showed that mitrochondria from CPIB-fed rats had an increased ability to oxidize labeled cholesterol in vitro. In the following experiment an attempt was made to prove or disprove the thesis that CPIB had a cholesterol mobilizing effect from tissue.