[Adenylic acid catabolism in thymocytes of the regenerating thymus in mice]

The T-cell non-peptide mitogenic factor isolated from the thymus stimulates thymus regeneration in mice previously treated with hydrocortisone. [8-14C]AMP catabolism in cortisone resistant thymocytes of mice has been investigated. Incorporation of radioactivity into hypoxanthine in cortisone resistant thymocytes is found to increase as compared with the total thymocyte population. Accumulation of labeled AMP catabolites in the form of hypoxanthine grows considerably after in vitro incubation of cortisone-resistant thymocytes with the non-peptide T-cell mitogenic factor. A large proportion of [8-14C]AMP catabolite radioactivity incorporated into cortisone-resistant thymocytes is excreted into the medium as hypoxanthine. It is supposed that hypoxanthine accumulation abrogates limitation of thymocyte DNA synthesis inhibited by relative excess of dGTP.