DNA Synthesis in the Thoracic-duct Lymphocytes of Rats during Recovery from Sub-lethal Irradiation

Abstract
Total-body irradiation of rats with doses of x-rays between 75–300 r produced a profound depression in the output of lymphocytes from thoracic-duct fistulae. Initially after the irradiation the percentage of large lymphocytes in the thoracic-duct lymph was decreased. During the recovery phase after a dose of 300 r, there was a marked increase in the percentage of large lymphocytes. DNA-synthesis in the large lymphocytes was studied by 32P incorporation in vivo and by the incorporation of tritiated thymidine in vitro. Following irradiation there was an increased number of large lymphocytes synthesizing DNA in unit time. The mechanism of this change is discussed.