Distribution of Label after Intragastric Administration of 7 Be-Labeled Carbon to Weanling and Aged Mice 1

Abstract

Abstract

Single doses of ⁷Be-labeled carbon particles prepared by proton bombardment of carbon black were administered by gavage to weanling (4 weeks) and aged (18 months) mice. Body distribution of ⁷Be radioactivity was determined 4 hr and 1, 2, 5, and 14 days later. The results were compared with those obtained after administration of a solution of ⁷BeCl₂. ⁷Be radioactivity in nonintestinal tissues was 17–58 times greater in mice gavaged with the soluble salt than in those gavaged with the particles, indicating that particle-bound ⁷Be was well confined to the gastrointestinal tract. Upper limits of the amount of labeled carbon remaining in intestinal Peyer's patches were as follows: 1 day: weanling, 1.8 × 10⁻³%, old, 5.5 × 10⁻³% 15 days: weanling, 3.3 × 10⁻⁵%, old, 8.4 × 10⁻⁵%. The particles are potentially useful as models for diesel emissions or other particulate pollutants.