Incorporation of Tritiated Thymidine into DNA after Oral Administration.

Abstract
Summary 1. H3TDR was administered via stomach tube to rats, mice, and guinea pigs. 2. Some ingested H3TDR was absorbed and labeled proliferating cells of gastrointestinal mucosa as early as 2 hours after ingestion in guinea pigs. 3. Labeling of diverse tissues including proliferative cells of the testes was seen in rats and mice 7I/2 hours after ingestion. 4. Some of the H3TDR was degraded to tritiated water while small amounts of non-volatile H3 activity were excreted in the urine. 5. The significance of absorption of H3TDR through intestinal mucosa is discussed as related to potential hazard.