Fig. 2.

Small intestinal 4F is transported into the intestinal lumen. A: ¹⁴C-l-4F (25 mg/kg, 1.8 μCi) was introduced via tail vein into the circulation of fasted male C57BL/6J mice. After 1 or 3 h (3 mice/time point), the animals were bled, euthanized, perfused, and dissected. The entire SIs were then rinsed three times with PBS, followed by three times with 0.6% taurocholate (TC) and three times with 1.0% Triton X-100 (TX). Radioactivity was determined in all of the rinses as well as in associated tissues, cecum contents, feces, and gall bladder contents (Gall bladder). B: Intact l-4F present in SI PBS rinse was determined by LC/MS/MS after 1 h following tail vein injection of l-4F (25 mg/kg) into C57BL/6J mice (n = 4). Error is reported as SEM.