Thymidine is a pyrimidine nucleotide that is found only in desoxyribonucleic acid (DNA). Autoradiographs of cells and tissues which have been exposed to radioactive thymidine have been shown to indicate DNA synthesis and may allow a study of cell migration. Thymidine labeled with tritium has been used increasingly in such studies.1 It is incorporated into the DNA of the nucleus during the period of synthesis during interphase, and the radioactive label may remain detectable after one or more divisions have taken place. Tritium emits weak β-radiation of short range which permits accurate localization by autoradiography.
In ocular tissues this method has been used to investigate the response to injury of the lens epithelium2,3 and of corneal endothelium,4 and to study cell production and migration in the epithelial layer of the cornea.5 In these studies, either the tritiated thymidine was injected into the anterior chamber, or excised
THOMSON DS, PIRIE A, OVERALL M. Autoradiography of Lens Epithelium After Parenteral Injection of Tritiated Thymidine. Arch Ophthalmol. 1962;67(4):464-469. doi:10.1001/archopht.1962.00960020464014