In vivo distribution of a carcinogenic hepatic peroxisome proliferator: whole-body autoradiography of [14C]ciprofibrate in the mouse.

The distribution of radiolabel in male mice was studied by whole-body autoradiography at intervals after oral administration of [14C]ciprofibrate, a carcinogenic hepatic peroxisome proliferator. Radioactivity was rapidly taken up by the liver and to a lesser extent by the brown fat within 9 h after oral dosing of ciprofibrate. The radioactivity levels in blood, interstitial fluid and fat decreased during the first 3 days after dosing, but the liver remained densely labeled. Between 3 and 27 days after dosing, liver exhibited a stippled pattern as a result of heavier labeling apparently around the central veins. The relatively low levels of radiolabel in extra-hepatic tissues observed after oral dosing, together with the prolonged retention in this region of the liver, is consistent with the hepatotropic effects (i.e. hepatic peroxisome proliferation and development of liver tumors) exerted by this compound.