Tetrahydrouridine

**Semantic type:** Nucleic Acid, Nucleoside, or Nucleotide|Pharmacologic Substance

**Definition:** A synthetic pyrimidine nucleoside analogue with biomodulating activity. Tetrahydrouridine increases the efficacy of the radiosensitizer cytochlor (5-chloro-2'-deoxycytidine) by inhibiting the enzyme deoxycytidine monophosphate (dCMP) deaminase and preventing the premature deamination of the cytochlor metabolite 5-chloro-2'-deoxycytidine monophosphate (CldCMP) to 5-chloro-2'-deoxyuridine monophosphate (CldUMP); in turn, this increases tumor concentrations of CldUMP which is then further anabolized and incorporated selectively into tumor DNA as CldU (5-chloro-2'-deoxyuridine). (NCI04)

**Synonyms:** - 2(1H)-pyrimidinone, tetrahydro-4-hydroxy-1-beta-D-ribofuranosyl- - TETRAHYDROURIDINE - THU - tetrahydrouridine