Thymidine (DThyd) is a cell synchronizing agent and a specific precursor of deoxyribonucleic acid. Thymidine inhibits DNA synthesis and can cause cell cycle arrest in the G1/S phase.

METHODS: Human hepatocellular carcinoma cells HepG2 were treated with Thymidine (300-1200 µM) and H2O2 (1 mM) for 0.5 h. DNA damage was detected by comet assay.
RESULTS: For the control and Thymidine alone groups, the samples appeared almost circular due to the absence of DNA damage. After exposure to 1.0 mM H2O2 for 0.5 h, a clear comet was observed, indicating DNA damage in this group. However, there was a decreasing trend in the extent of DNA damage in the three combination groups as the concentration of Thymidine pretreatment increased. [1]
METHODS: Jurkat, MOLT4 and NALM6 cells were treated with Thymidine (2 mM) for 18 h.
RESULTS: Thymidine arrests the cell cycle at the G1/S boundary. [2]

METHODS: To investigate the effects of folate analogs on superantigen-reactive peripheral T cells in vivo, Thymidine (500 mg/kg) was injected intraperitoneally into MTX- or tomudex-administered mice twice daily for ten days.
RESULTS: Both MTX and tomudex blocked the expansion and accelerated the peripheral clearance of Vβ8-selective T cells. Thymidine administration completely eliminated this effect, suggesting that inhibition of glycoside synthase (TS), but not other folate-dependent enzymes, is the predominant mechanism. [3]