HPLC radiochromatograms of a 14C-C3 standard, and extracted plasma samples taken at 2 h and 18 h after a single 1.1 mg/kg i.p. administration of 14C-C3 in mice. Similar amounts of total radioactivity were chromatographed for each sample. C3 elutes at 27 min, with the two minor mono-decarboxylation products, present in the original preparation, appearing at 31 and 40 min, respectively. Both the 2 h and 18 h plasma samples were essentially identical to the original C3 stock. i.p, = intraperitoneal