Hydrocortisone regulation of thymidine kinase in thymus involution and hematopoietic tissues

Olga Greengard, Raymund Machovich

Research output: Contribution to journalArticle

21 Citations (Scopus)


Thymus involution, initiated by hydrocortisone treatment, was accompanied by a 90% decrease of thymidine kinase activity per g tissue. The concentration of six other enzymes remained essentially unchanged and that of two increased significantly, indicating that hydrocortisone has a selective effect on the enzymic composition of this organ. Hydrocortisone also decreased the level of thymidine kinase in two erythropoietic organs, fetal liver and neonatal spleen. These results indicate a close connection between thymidine kinase and the effect of glucocorticoids on organs involved in blood cell turnover. The effect of hydrocortisone on thymidine kinase levels does not necessarily coincide with that on cellularity. In spleen of 3-4-day-old rats the hormone did not alter the number of nuclei per g. In fetal liver an injection of hydrocortisone can cause maximal loss of thymidine kinase before there is any detectable loss in the number of hematopoietic cells. These results suggest that intracellular changes in enzyme concentrations precede alterations in cytocomposition.

Original languageEnglish
Pages (from-to)382-388
Number of pages7
JournalBBA - General Subjects
Issue number2
Publication statusPublished - Dec 29 1972


ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology

Cite this