Fischer 344

Fischer 344 Inbred Rat Model
  • Cryopreserved
  • Rat
  • Albino
Model No.NomenclatureGenotype
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Nomenclature: F344/NTac

  • Used for cancer research, toxicology, and aging studies


Heston received stock from Curtis of Columbia University Institute for Cancer Research in 1949. NIH received stock from Heston in 1951. Taconic received axenic breeders at F143 from the NIH Animal Genetic Resource in 1984. The rats were refreshed at F173 by incrossing rats received from the NIH Genetic Resource in 1997 to preserve genetic continuity. The Taconic foundation colony was at F190 in 2005.


Strain Type:Inbred
Coat Color:Albino
Coat Color Loci: Tyrc
Genetic Background:F344
Coat Color Loci: Tyrc

Other Genetic Notes:

  • Strain Pro?le: Aco1b, Amy2a, Anpepa, Es1a, Es2a, Es3a, Es4b, Es6a, Fh1b, Hao1a, Hbba, Pepcb
  • Immunology: RT1-Al, RT2a, RT3b

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F344 Physiological Data Summary (March 2004; N=10/group):

ParameterUnitsF344 MalesF344 Females
Serum ChemistryAvg ± S.D  
Calciummg/dL12.6 ± 0.412.6 ± 0.3
Phosphorousmg/dL11.5 ± 1.111.1 ± 0.5
Glucosemg/dL78 ± 2191 ± 14
Creatininemg/dL0.3 ± 0.00.3 ± 0.0
BUNmg/dL13.1 ± 116 ± 1
Total Bilirubinmg/dL0.1 ± 0.00.1 ± 0.0
ALKU/L412 ± 28295 ± 19
ALT U/LU/L45 ± 638 ± 3
Total Proteing/dL6.6 ± 0.26.7 ± 0.2
Blood Counts
Red Blood CellsX10^6/uL8.097 ± 0.3273828.775 ± 0.279016
Nucleated RBCX10^6/uL00
Hemoglobing/dL15.6 ± 0.516.7 ± 0.5
Hematocrit%50.3 ± 2.154.4 ± 1.2
MCVfL62 ± 162 ± 1
MCHpG19.3 ± 0.319.0 ± 0.2
MCHC%31.1 ± 0.530.7 ± 0.3
PlateletsX10^3/uL787 ± 191799 ± 75
White Blood Cellsx10^3/uL7.283 ± 2.349629.924 ± 2.01759
Neutrophilx10^3/uL1.247 ± 0.4451.395 ± 0.505
Lymphocytex10^3/uL5.768 ± 1.9127.983 ± 1.754
Monocytesx10^3/uL0.235 ± 0.1540.461 ± 0.327
Eosinophilx10^3/uL0.034 ± 0.0740.149 ± 0.213
Organ Weights   
Stomachg1.188 ± 0.1311.000 ± 0.075
Ileumg3.877 ± 0.5033.625 ± 0.457
Colong0.942 ± 0.1640.726 ± 0.252
Lungsg1.056 ± 0.0470.959 ± 0.124
Heartg0.744 ± 0.0840.581 ± 0.039
Liverg7.051 ± 0.7045.248 ± 0.465
Spleen/Pancreasg0.953 ± 0.1750.829 ± 0.171
Kidney (L)g0.708 ± 0.0540.589 ± 0.052
Kidney (R)g0.701 ± 0.0600.594 ± 0.047
Testes (L)g0.982 ± 0.100-
Testes (R)g0.971 ± 0.118-
Ovary (L)g-0.055 ± 0.007
Ovary (R)g-0.055 ± 0.012
pH-6.65 ± 0.416.7 ± 0.26
Specific Gravity-1.02 ± 0.011.02 ± 0.01

Phenotyping Procedures:

Animal Receipt and Maintenance

A quantity of twenty rats (ten males and ten females) was submitted for testing, strain identified as Line F344 (F344/NTac), age 7 weeks. Rats were received at RBU 3, Taconic Biotechnology, Albany NY and acclimated for three days on irradiated NIH #31M rodent diet and sterilized water ad lib, sterile contact bedding (paper chip) and a 12:12 light:dark cycle. All animals appeared normal during this period and routine health surveillance of this colony detected no microbial pathogens. Rats were assigned study unique identification numbers (males 1-10, females 11-20).


All rats were fasted in metabolic cages and an overnight urine sample was collected. Urine analysis was performed using Multistix 10 SG (Bayer). Strips were read and recorded as per the manufacturer's instructions, and the results are presented in Table 2.

Clinical Chemistry and Hematology

A terminal blood sample was taken from Carbon Dioxide - anesthetized rats via cardiac puncture. The collected blood was divided into two samples. One sample was treated with EDTA and stored at 4°C for hematological evaluation. Another sample was allowed to clot at 4°C for 30 minutes, and then centrifuged at 7000rpm for 10 minutes, and the serum was decanted and frozen at -80°C for clinical chemistry analysis. A slide smear was made from a single drop of whole blood. Frozen serum, chilled whole blood, and slides were delivered to LabCorp (RTP, NC) for analysis; the results are presented in Table 3. Unless otherwise indicated, serum chemistry data is generated from a Hitachi 717 automated analyzer and hematological data is generated from a Celldyne 3500. WBC differential counts are performed manually.

Necropsy and Organ Weights

All rats were euthanized and bodyweights were recorded. Representative tissues were collected, weighed, and immersion fixed in 10% Neutral Buffered Formalin. Tissues were delivered to the Taconic lab for histological preparation and evaluation. Tabulation of organ weights is presented in Table 4. The pathologist's summary and detailed histological descriptions follow.


All animals were thrifty on arrival and appeared clinically normal. Locomotor behavior was normal and there were no visible lesions or discharges at the mucous membranes. All tissues appeared normal on gross necropsy evaluation and weights were within normal limits. There were no unusual findings upon collection of these tissues nor otherwise observed in the body cavities.

The overall profile of these rats is consistent with expectations of a general-purpose rat. None of the parameters are indicative of impaired system function.

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