IUPAC Name: 1-Ethyl-1-nitrosourea
The MF of 1-Ethyl-1-nitrosourea (CAS NO.759-73-9) is C₃H₇N₃O₂.

                                    
The MW of 1-Ethyl-1-nitrosourea (CAS NO.759-73-9) is 117.11.
Synonyms of 1-Ethyl-1-nitrosourea (CAS NO.759-73-9): N-Ethyl-N-nitrosourea ; Urea, N-ethyl-N-nitroso- ; 1-Ethyl-1-nitrosomocovina ; Aethylnitroso-harnstoff ; Aenh
Product Categories: Miscellaneous Reagents
Apperance: Yellow-pink crystals or off-white powder
Index of Refraction: 1.532 
EINECS: 212-072-2
Density: 1.35 g/ml
Flash Point: 63.8 °C
Boiling Point: 181.8 °C
Melting Point: 103-104 °C
Storage temp: -20 °C

Bill Russell (1951) created a landmark in the field of mouse genetics by creating a specifically designed mouse strain, the T (test) stock that was used in genetic screens for testing mutagens such as radiations and chemicals. The T-stock mouse harbors 7 recessive, viable mutations affecting easily recognizable traits. At the Oak Ridge National Laboratory, Russell's initial goal was to determine the rate of inheritable gene mutations in the germ line induced by radiations. Thus he decided to use T-stock mice in order to define how often a set of loci could be mutated with radiations. Since the mutations in the T-stock mouse were recessive, the progeny would have a wild type phenotype (as a result of crossing a mutant [eg.s/s mutant male] to a wild type female [+/+]). Thus with any progeny carrying a mutation induced by radiation at one of the 7 loci, would exhibit the mutant phenotype in the first generation itself. This approach, the specific locus test (SLT) allowed Russell to study a wide range of specific mutations and to calculate the mutation rates induced by radiations.
In addition to studying the effect of radiation for SLT, Russell et al. were also interested in studying the effect of chemical mutagens such as procarbazine and ethylnitrosourea for SLT. At that time, procarbazine was the most potent chemical mutagen known to cause a significant spermatogonial mutagenesis in an SLT, although at a rate one-third of that of X-rays. Russell's earlier mutagenesis work on Drosophila using diethylnitrosoamine (DEN) triggered them to use DEN for the SLT. However, DEN needs to be enzymatically converted into an alkylating agent in order to be mutagenic and probably this enzymatic activation was not sufficient in mammals. This could be illustrated by the extremely low mutation rate in mice given by DEN (3 in 60,179 offsprings). To overcome this problem, a new mutagen, N-ethyl N-nitrosourea (ENU), an alkylating agent, which does not need to be metabolised, was suggested to be used by Ekkehart Vegel to Russell et al. The ENU (250 mg/kg) induced mice underwent a period of sterility for 10 weeks. After recovery, 90 males were crossed to the T-stock females and 7584 pups were obtained.Their results showed that a dose of 250 mg/kg of ENU was capable of producing a mutation rate 5 times higher than that obtained with 600R (1R = 2.6 x10^-4 coulombs/kg) of acute X-irradiation. This rate was also 15 times higher to that obtained with procarbazine (600 mg/kg).
To overcome the problem of initial period of sterility, the Russell group showed that instead of injecting one large dose of ENU, a fractionated dose (100 mg/kg) on a weekly schedule permitted a total higher dose (300-400 mg/kg) to be tolerated. This further showed that the mutation freq

Ever since the discovery of ENU as the most potent mutagen by Russell et al. it has been used in forward (phenotype based) genetic screens with which one can identify and study a phenotype of interest.

NTP 10th Report on Carcinogens. IARC Cancer Review: Group 2A IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 7 (1987),p. 56.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) ; Human Limited Evidence IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 17 (1978),p. 191.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) ; Animal Sufficient Evidence IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 17 (1978),p. 191.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) ; IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 1 (1972),p. 135.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) . EPA Genetic Toxicology Program. Community Right-To-Know List. Reported in EPA TSCA Inventory.

Confirmed carcinogen with experimental carcinogenic, neoplastigenic, tumorigenic, and teratogenic data. Poison by ingestion, subcutaneous, intraperitoneal, and intravenous routes. Human mutation data reported. When heated to decomposition it emits toxic fumes of NO_x. See also N-NITROSO COMPOUNDS.Safety information of 1-Ethyl-1-nitrosourea (CAS NO.759-73-9):
Hazard Codes  T
Risk Statements 
45 May cause cancer
46 May cause heritable genetic damage
61 May cause harm to the unborn child
20/21/22 Harmful by inhalation, in contact with skin and if swallowed
Safety Statements 
53 Avoid exposure - obtain special instruction before use
22 Do not breathe dust
36/37/39 Wear suitable protective clothing, gloves and eye/face protection
45 In case of accident or if you feel unwell, seek medical advice immediately (show label where possible)
RIDADR  UN 2811 6.1/PG 3
WGK Germany  3
RTECS  YT3150000
HazardClass  6.1(b)
PackingGroup  III

 N-Ethyl-N-nitrosourea is a highly potent mutagen. For a given gene in mice, ENU can induce 1 new mutation in every 700 gametes. It is also toxic at high doses.The chemical is an alkylating agent, and acts by transferring the ethyl group of ENU to nucleobases (usually thymine) in nucleic acids. Its main targets are the spermatogonial stem cells, from which mature sperm are derived.