[Effect of non-radioactive thymidine on mitosis in bone marrow]

Intraperitoneal administration of thymidine into albino mouse (strains CD-1) at dose of 4.8 mg (180 mg/kg) increases mitotic rate in bone marrow at 6, 9 and 12 hours; this effect begins at 3 hours and disappears at 24 hours. It is suggested that thymidine increases mitotic rate by an indirect mechanism, stimulating DNA synthesis during S phase through activation of thymidoquinase. Control group (saline solution without thymidine) showed reduction in mitotic rate; such a finding has no explanation as yet.