Metabolic Fate of Injected C 14 -Phytosterols. ∗ ‡

Summary

Data are presented on the comparative tissue distribution of C¹⁴-free and esterified sterols following injection of cho-lesterol-4-C¹⁴ and C¹⁴-phytosterols to normal and bile-fistula rats. At the end of 24 hours a large proportion of the injected C¹⁴-phytosterols and cholesterol-4-C¹⁴ was recovered in the liver. All tissues examined (serum, liver, small intestine and adrenal) showed the presence of esterified C¹⁴-phytosterols, but less was esterified than with cholesterol-4-C¹⁴. A much larger proportion of the injected C¹⁴-phytosterols was recovered in the feces and intestinal contents than in the cholesterol-4-C¹⁴ group. Conversion of the injected C¹⁴-phytosterols to bile acid was observed; a larger proportion of the injected C¹⁴-activity was recovered in the bile as C¹⁴-sterol than with injected cholesterol-4-C¹⁴. No conversion of C¹⁴-phytosterols to cholesterol or related sterols could be demonstrated.