University of California Berkeley seal E. O. Lawrence Berkeley National Laboratory seal
The Carcinogenic Potency Project

N-Nitrosopyrrolidine (CAS 930-55-2)
SMILES, InChI and Structure are below.
Rats and Mice: Cancer Test Summary
Rat Target Sites Mouse Target Sites TD50 (mg/kg/day)
Male Female Male Female Rat Mouse
kid liv liv vsc tba no test 0.799m,P 0.679

Hamsters: Cancer Test Summary
Hamster Target Sites TD50
Male Female
liv liv 14.2m

Key to the Table Above

Positivity: For each chemical with a positive (carcinogenic) experiment in the Carcinogenic Potency Database (CPDB), results are included on carcinogenic potency (TD50) in each species and target sites in males and females. Positivity is determined by an author’s opinion in a published paper. If all experimental results in the CDPB are negative in a sex-species group, “no positive” appears. If the CPDB has no experiments in the sex-species group, “no test” appears. The summary presents the strongest evidence of carcinogenicity in each group. If there are both positive and negative experiments in a sex-species, the negative results are ignored in this Summary Table.
Target Site Codes:   kid = kidney. liv = liver. tba = all tumor bearing animals. vsc = vascular system. Target sites are listed if any author of published experimental results concluded that tumors were induced in that organ by the test agent. If there is more than one positive experiment in a sex-species, target sites listed may be from more than one experiment, e.g. if liver and lung are both listed, then liver may have been a target in one experiment and lung in another.
TD50: Our standardized measure of carcinogenic potency, TD50, is the daily dose rate in mg/kg body weight/day to induce tumors in half of test animals that would have remained tumor-free at zero dose. Whenever there is more than one positive experiment in a species, the reported TD50 value is a Harmonic Mean calculated using the TD50 value from the most potent target site in each positive experiment.
Superscripts:   m = There is more than one positive experiment in the species, and TD50 values from each positive experiment are used in the calculation of the reported Harmonic mean of TD50. P = 100% of dosed animals had tumors at a target site in an experiment in this species.

The Carcinogenic Potency Database (CPDB) is a unique and widely used international resource of the results of 6540 chronic, long-term animal cancer tests on 1547 chemicals. The CPDB provides easy access to the bioassay literature, with qualitative and quantitative analyses of both positive and negative experiments that have been published over the past 50 years in the general literature through 2001 and by the National Cancer Institute/National Toxicology Program through 2004. The CPDB standardizes the diverse literature of cancer bioassays that vary widely in protocol, histopathological examination and nomenclature, and in the published author’s choices of what information to provide in their papers. Results are reported in the CPDB for tests in rats, mice, hamsters, dogs, and nonhuman primates.

For each experiment, information is included on species, strain, and sex of test animal; features of experimental protocol such as route of administration, duration of dosing, dose level(s) in mg/kg body weight/day, and duration of experiment; experimental results are provided on target organ, tumor type, and tumor incidence; carcinogenic potency (TD50) and its statistical significance; shape of the dose-response, author’s opinion as to carcinogenicity, and literature citation.

Only tests with dosing for at least ¼ the standard lifespan of the species and experiment length at least ½ the lifespan are included in the CPDB. Only routes of administration with whole body exposure are included. Doses are standardized, average dose rates in mg/kg/day. A description of methods used in the CPDB to standardize the diverse literature of animal cancer tests is presented for: 1) Criteria for inclusion of experiments 2) Standardization of average daily dose levels and 3) TD50 estimation for a standard lifespan. See Methods for other details.

TD50 provides a standardized quantitative measure that can be used for comparisons and analyses of many issues in carcinogenesis. The range of TD50 values across chemicals that are rodent carcinogens is more than 100 million-fold. More than half the chemicals tested are positive in at least one experiment.

A plot of all results on each experiment in the CPDB for this chemical is presented below. These results are the source information for the Cancer Test Summary table above.

N-Nitrosopyrrolidine: All Experiments and Citations in CPDB

The definition of each code in the plot below will appear in a pop-up window when the field name in the header line is clicked, e.g., Strain, Site, Path. Each numbered line starts a new experiment and reports protocol information in black. Average daily dose-rates per kg body weight per day are in green. Remaining lines report experimental results in blue.

Abbreviations of fields in header line: # = the line number in the plot of all CPDB chemicals; Xpo = duration of dosing; Xpt = duration of experiment; Site = tissue; Path = tumor type; DR = dose-response; AuOp = author’s opinion about carcinogenicity; LoConf, UpConf = confidence limits (99%) on TD50; Inc = tumor incidence for each dose group.

See Guide to reading the plot for details on each field, using an example of one experiment.

See Help to improve readability, or to fit the plot onto the screen or a printed page.

Chemical (Synonym) CAS
# Species Sex Strain Route Xpo+Xpt PaperNum        0 Dose  1 Dose 2 Dose  3 Dose          Literature Reference or NCI/NTP:Site Path
Site Path Notes   TD50  DR Pval    AuOp LoConf UpConf   Cntrl   1 Inc  2 Inc   3 Inc                                                        Brkly Code

N-NITROSOPYRROLIDINE 930-55-2 4635 H f syg wat 24m24 1503 0 .573mg 2.18mg 4.50mg Ketkar;zkko,104,75-79;1982 liv hct 35.9mg * P<.008 + 12.4mg 0/50 0/30 1/30 3/30 tba mix 8.44mg * P<.002 4.27mg 39.7mg 3/50 2/30 10/30 8/30 4636 H m syg wat 24m24 1503 0 .504mg 1.92mg 3.96mg liv hct 8.88mg * P<.0005 + 4.67mg 20.4mg 0/50 1/30 2/30 10/30 liv hae * P<.2 21.2mg n.s.s. 0/50 0/30 0/30 1/30 tba mix 9.26mg * P<.007 4.14mg 8/50 3/30 4/30 13/30 4637 M m swi gav 76w76 1713 0 1.19mg Shah;zkko,109,203-207;1985 tba mix e .679mg P<.002 + .309mg 2.84mg 1/20 10/20 4638 R m chm wat 84w84 1774 0 3.00mg Chung;canr,46,1285-1289;1986 liv hpc .659mg P<.0005 + .340mg 1.35mg 0/23 20/23 liv nnd 1.13mg P<.0005 + .601mg 2.40mg 0/23 16/23 liv clc 14.8mg P<.1 + 3.63mg n.s.s. 0/23 2/23 4639 R b clw wat 30m30 1958 0 34.0ug 69.0ug .137mg .275mg .550mg 1.10mg 1.65mg 2.20mg 2.75mg 3.30mg 4.40mg 5.50mg 6.60mg 8.80mg 17.6mg Gray;canr,51,6470-6491;1991 liv hct e 1.70mg * P<.0005 + 1.24mg 2.36mg 8/246 0/12 0/12 1/12 5/12 6/12 9/12 12/12 12/12 11/12 10/12 12/12 9/12 10/12 11/12 12/12 liv hpc e 2.20mg * P<.0005 + 1.63mg 3.03mg 2/246 0/12 0/12 1/12 5/12 4/12 7/12 10/12 11/12 10/12 9/12 11/12 9/12 9/12 11/12 12/12 bil ben e 99.7mg * P<.003 + 40.1mg 2/246 0/12 0/12 0/12 1/12 0/12 1/12 0/12 0/12 0/12 1/12 0/12 2/12 2/12 2/12 0/12 nsp tum e * P<.04 86.1mg n.s.s. 0/246 0/12 0/12 0/12 0/12 0/12 0/12 0/12 0/12 1/12 0/12 0/12 0/12 0/12 1/12 0/12 4640 R f f34 wat 7m26 1795 0 1.00mg Michejda;canr,46,2252-2256;1986/pers.comm. liv hpc e noTD50 P<.0005 + n.s.s. .409mg 0/20 20/20 liv nnd e 2.51mg P<.04 + .915mg n.s.s. 1/20 6/20 liv hes e 15.0mg P<.3 + 2.44mg n.s.s. 0/20 1/20 liv clc e 15.0mg P<.3 + 2.44mg n.s.s. 0/20 1/20 tba mix e noTD50 P<.6 + n.s.s. n.s.s. 19/20 20/20 4641 R f f34 wat 12m26 2022 0 1.65mg Lijinsky;clet,12,99-103;1981 liv hpc e .439mg P<.0005 + .179mg 1.04mg 1/20 19/20 liv mix e .439mg P<.0005 + .179mg 1.04mg 1/20 19/20 liv clc e 4.49mg P<.007 + 1.70mg 51.8mg 0/20 5/20 liv cho e 7.95mg P<.04 2.40mg n.s.s. 0/20 3/20 liv lyp e 7.95mg P<.04 2.40mg n.s.s. 0/20 3/20 liv sar e 25.2mg P<.3 4.10mg n.s.s. 0/20 1/20 tba tum e no dre P=1. .326mg n.s.s. 20/20 19/20 4642 R f mrw wat 16m24 228 0 5.21mg Greenblatt;jnci,48,1687-1696;1972/1973 liv hpc e 1.81mg P<.0005 + .802mg 4.45mg 0/20 13/15 tba mix e 4.49mg P<.3 1.06mg n.s.s. 14/20 13/15 4643 R m mrw wat 16m24 228 0 3.65mg liv hpc e 1.58mg P<.0005 + .731mg 3.93mg 0/20 12/15 tes pms e 8.21mg P<.007 2.82mg 0/20 4/15 tba mix e 2.03mg P<.004 .807mg 16.5mg 6/20 12/15 4644 R b sda wat 23m30 371 0 .300mg 1.00mg 3.00mg 10.0mg Preussmann;zkko,90,161-166;1977 liv hpc as 3.26mg Z P<.0005 2.23mg 5.01mg 0/61 0/60 13/62 30/38 (9/24) liv hpa as 55.5mg * P<.005 20.9mg 0/61 3/60 4/62 1/38 5/24 tba mal as 2.37mg Z P<.0005 + 1.60mg 3.90mg 6/61 12/60 20/62 32/38 (11/24) tba ben as 71.1mg * P<.2 20.9mg n.s.s. 5/61 7/60 9/62 3/38 6/24 4645 R m sda wat 20m30 1717m 0 .657mg Hoos;clet,26,77-82;1985 liv hpc .648mg P<.0005 + .454mg .958mg 0/80 53/80 tba mal .631mg P<.0005 .412mg 1.10mg 19/80 60/80 4646 R m sda wat 10m30 1717n 0 .657mg liv hpc .489mg P<.0005 + .346mg .712mg 0/80 61/80 tba mal .501mg P<.0005 .333mg .826mg 19/80 65/80 4647 R m sda wat 37m38 1838 0 28.6ug 95.0ug .286mg Berger;carc,8,1635-1643;1987/pers.comm. liv mix a 2.43mg * P<.0005 + 1.44mg 4.68mg 3/500 1/80 4/80 17/80 liv hpc a 4.06mg * P<.0005 + 2.14mg 9.15mg 0/500 1/80 0/80 12/80 liv hpa a 8.13mg * P<.0005 + 3.42mg 31.2mg 1/500 0/80 2/80 5/80 unt tum a 7.03mg Z P<.1 + 1.78mg n.s.s. 1/500 2/80 1/80 (0/80) git mix a 14.9mg * P<.4 + 3.25mg n.s.s. 26/500 6/80 7/80 6/80 liv hmm a 55.7mg * P<.3 9.07mg n.s.s. 0/500 0/80 1/80 0/80 tba mal a 2.03mg * P<.007 + .933mg 38.1mg 144/500 23/80 28/80 35/80 tba ben a no dre P=1. 1.18mg n.s.s. 362/500 63/80 59/80 55/80

Mutagenicity in Salmonella: positive
SMILES Code for N-Nitrosopyrrolidine: O=NN1CCCC1
InChI Code for N-Nitrosopyrrolidine: InChI=1/C4H8N2O/c7-5-6-3-1-2-4-6/h1-4H2
Source for SMILES and InChI: USEPA Distributed Structure-Searchable Toxicity (DSSTox) Database
Chemical Structure for N-Nitrosopyrrolidine: Chemical Structure
Source for structure: National Library of Medicine ChemIDPlus

See full CPDB Summary Table on 1547 chemicals. See Full CPDB for all results on 6540 experiments of 1547 chemicals.

A complete list of CPDB chemicals, which is searchable by name or by CAS number, is available here.

For a compendium of CPDB results organized by target organ, which lists all chemicals in each species that induced tumors in each of 35 organs, see Summary Table by Target Organ.

The CPDB is available in several formats that permit printing and downloading into spreadsheets and statistical databases.

  1. A plot of the CPDB presents results of 1547 experiments on 6540 chemicals in an easily readable format that has been used in publications of the CPDB.
  2. A Screen version plot for use on a single computer screen, with the same data.
  3. Excel version of the same data.
  4. Tab-separated versions of the same data, which can be easily read into databases.

A Supplementary Dataset gives details on dosing and survival for each experiment.

Relatively precise estimates of the lower confidence limit on the TD10 (LTD10) are readily calculated from the TD50 and its lower confidence limit, which are reported in the CPDB. For researchers and regulatory agencies interested in LTD10 values, we provide them in an Excel spreadsheet.

PDF versions of our publications of analyses using the CPDB are available, organized by year and by research topic.

Carcinogenic Potency Database Project (CPDB) Home Page
For more information about this Web Page, contact Specialized Information Services (
Last updated: October 3, 2007

PDF documents are best viewed with the free Adobe® Reader
Excel documents are best viewed with the free Excel® Viewer