Open AccessSTUDIES ON THE REGULATION OF LYMPHOCYTE PRODUCTION IN THE MURINE THYMUS AND SOME EFFECTS OF A CRUDE THYMUS EXTRACT
Author(s) -
Olsson Lennart,
Claësson Mogens H.
Publication year - 1975
Publication title -
cell proliferation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.647
H-Index - 74
eISSN - 1365-2184
pISSN - 0960-7722
DOI - 10.1111/j.1365-2184.1975.tb01235.x
Subject(s) - spleen , dna synthesis , in vivo , biology , lymphocyte , microbiology and biotechnology , in vitro , immunology , andrology , biochemistry , medicine
Cell proliferation in the murine thymus was studied in vivo under normal conditions and from 0 to 24 hr after a single injection of a water‐soluble extract from mouse thymus, mouse spleen, and mouse skin. The thymus extract reduced during the first 24 hr the mitotic activity 40%; the spleen extract had a weaker inhibitory effect. The skin extract had no such effect. The thymus extract and spleen extract inhibited the flux of cells into the S phase 0–8 hr after the injection of the extract. Initial labelling index was also reduced in this period. Eight hours after injection of the thymus or spleen extracts the inhibited cells initiated DNA synthesis. The rate of progression of blast cells through the cell cycle was normal 24 hr after the injection of the extracts. It was deduced from the analysis that the thymus extract inhibits processes triggering Go/Gi cells into DNA synthesis, the inhibition of G 2 efflux being of minor importance. Finally a model for the regulation of proliferating thymic blast cells and the emigration of small lymphocytes from the thymus is proposed.