title: The effect of steroids on the circulating lymphocyte population. V. Effect of prednisolone treatment on cell size and life span of the thoracic duct lymphocyte population in normal and neonatally thymectomized rats. A radioisotope study.
abstract: Using 3H-TdR isotope labelling in vivo, the effect of a high corticosteroid dose was correlated to cell size and life span of thoracic duct lymphocytes in rats. The lymphocytopenia in thoracic duct lymph during the involution phase (3 hrs after treatment) was a marked depletion of small lymphocytes, followed by a restitution to pretreatment cell levels within one day. The original lymphocyte population had a higher per cent of labelled small lymphocytes (50%) in comparison to the returning population which contained fewer (35%) small labelled cells. Label index (i.e. labelled cells of a certain cell size in percent of total cell number) was unchanged for all cell sizes during both involution and restitution phases. This unchanged label index profile as well as an earlier described unchanged cell size distribution support the hypothesis of lymphocyte trapping and redistribution as a major effect of a single prednisolone dose. The decrease of labelled small lymphocytes in the returning cell population can, however, also agree with a minor lymphocytolytic effect on circulating small lymphocytes. Our data do not support the hypothesis of two different lymphocyte populations with different life span. Neither could a redistribution of lymphocytes be found in any lymphoid tissue compartment or in femur bone marrow, during the involution phase after corticosteroid treatment.
mesh_terms: D000818:Animals; D002452:Cell Count; D002470:Cell Survival / Q000187:drug effects; D008214:Lymphocytes / Q000166:cytology / Q000187:drug effects*; D011239:Prednisolone / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013897:Thoracic Duct; D013934:Thymectomy; D013936:Thymidine / Q000378:metabolism; D014316:Tritium
chemical_list: D014316:Tritium; D011239:Prednisolone; D013936:Thymidine