Murine thymic multicellular complexes during latency period after methylnitrosourea (MNU) injection.

The number of TNC complexes and of stroma cell-thymocyte rosettes was examined during the preleukemic period in mice given MNU to induce leukemia. In parallel, numbers of the complexes were studied following administration of hydrocortisone one day before administering MNU, i.e. after the procedure which clearly inhibited manifestation of induced leukemias. Administration of MNU with or without hydrocortisone is followed by disappearance of TNC complexes and stroma cell-thymocyte rosettes followed by their regeneration between 2 and 6 weeks after MNU. Relative rates of regeneration were different in MNU treated versus MNU + hydrocortisone treated animals.