Fate of Intraintestinal Thymocytes Labeled with 125 lododeoxyuridine or Tritiated Thymidine 1 2

Abstract

Summary

A suspension of thymocytes labeled with ¹²⁵IUdR or 3 HTdR was injected into the jejunum of mice. The bulk of the radioactivity disappeared within few hours from the intestine and was recovered principally in the urine. This indicated a very rapid breakdown of labeled thymic cells, reabsorption and subsequent elimination of the tracer in the kidney. In mice injected with cells labeled with 3 HTdR, the initial rapid loss of radioactivity was of shorter duration, and slower during the second phase, presumably due to more extensive reutilization and/or prolonged persistence of acid-soluble radioactivity. Pretreatment of the recipients with antibiotics did not significantly reduce the rate of radioactivity loss.