These mice carry a spontaneous mutation at the Tshr locus characterized by growth retardation, low thyroid hormone levels, elevated thyroid stimulating hormone (TSH), hypoplastic thyroid glands, and stereocilia defects of the cochlear hair cells resulting in deafness.Read More +
Mice homozygous for the hypothyroid spontaneous mutation (Tshrhyt) are characterized by growth retardation, low thyroid hormone levels, elevated thyroid stimulating hormone (TSH) and hypoplastic thyroid glands. Homozygous mice of both sexes are infertile but fertility as well as growth can be restored by treatment with thyroid hormone. The mice do not respond to exogenous TSH. Homozygous mutant mice also have delayed eye-opening and raising of the ear-pinna to 17 and 20 days of age respectively, and display auditory defects characterized by morphologic abnormalities of the stereocilia on both inner and outer hair cell systems. Administration of thyroxin from conception through postnatal day 28 ameliorates the phenotypes of hearing, body weight, and age of eye-opening and pinna-raising to a greater degree than administration only prenatally and a much greater degree than administration only postnatally (Sprenkle et la., 2001).
|Allele Synonym(s)||hyt; pet; petite|
|Gene Symbol and Name||Tshr, thyroid stimulating hormone receptor|
|Strain of Origin||RF/J|
|Molecular Note||The mutation in the hypothyroid mouse is a C-to-T transition at coding nucleotide 1667. This results in a substitution of proline with leucine at position 556 (p.P556L) in transmembrane domain IV of the encoded protein.|
This strain carrying the hypothyroid mutation is maintained by mating heterozygous females with homozygous males. Male mice used for breeding at The Jackson Laboratory are implanted with a 60-day timed-release capsule containing 5 mg of L-thyroxine under the skin. Homozygous females are not used for breeding because implanted L-thyroxine will pass through the milk to nursing pups. Implantation is done under the skin at the back of the neck at 5-7 weeks of age. Some male homozygotes will begin breeding prior to implantation, and if this is the case, we do not use the capsule. Capsules are not replaced at the end of 60 days, but our breeder pairs here at The Jackson Laboratorywill often continue to breed for up to a year. Capsules may be purchased from Innovative Research of America, Sarasota, FL. The Jackson Laboratory does not implant L-thyroxine capsules in male homozygous mice prior to distribution.
When using the hypothyroid mouse strain in a publication, please cite the originating article(s) and include JAX stock #000805 in your Materials and Methods section.