Quantitative trait loci associated with elevated thyroid-stimulating hormone in the Wistar-Kyoto rat.
Thyroid hormones are essential for the regulation of developmental and physiological processes. The genetic factors underlying naturally occurring variability in mammalian thyroid function are, however, only partially understood. Genetic control of thyroid function can be studied with animal models such as the inbred Wistar-Kyoto (WKY) rat strain. Previous studies established that WKY rats have elevated TSH, slightly elevated total T3, and normal total T4 levels compared with Wistar controls. The present study confirmed a persistent 24-h elevation of TSH in WKY rats compared with the Fisher 344 (F344) rat, another inbred strain. Acute T3 challenge (25 microg/100 g body weight ip) suppressed serum TSH and T4 levels in both strains. Quantitative trait locus analysis of elevated TSH in a reciprocally bred WKY x F344 F2 population identified one highly significant locus on chromosome 6 (LOD=11.7, TSH-1) and one suggestive locus on chromosome 5 (LOD=2.3, TSH-2). The confidence interval of TSH-1 contains the TSH receptor and type 2 deiodinase genes, and TSH-2 contains the type 1 deiodinase gene. The WKY alleles of each gene contain sequence alterations, but additional studies are indicated to identify the specific gene or genes responsible for altered regulation of the thyroid axis. These findings suggest that one or more genetic alterations within the TSH-1 locus significantly contribute to the altered thyroid function tests of the WKY rat.
Baum
Amber E
AE
Department of Psychiatry and Behavioral Science, Northwestern University Feinberg School of Medicine, 303 East Chicago Avenue, Chicago, Illinois 60611, USA.
Solberg
Leah C
LC
Kopp
Peter
P
Ahmadiyeh
Nasim
N
Churchill
Gary
G
Takahashi
Joseph S
JS
Jameson
J Larry
JL
Redei
Eva E
EE
D020413:3' Untranslated Regions; D000818:Animals; D002940:Circadian Rhythm / Q000502:physiology; D005260:Female; D016678:Genome; D007453:Iodide Peroxidase / Q000235:genetics / Q000378:metabolism; D008297:Male; D009419:Nerve Tissue Proteins / Q000235:genetics; D040641:Quantitative Trait Loci; D051381:Rats; D011916:Rats, Inbred F344; D011921:Rats, Inbred WKY / Q000235:genetics*; D013972:Thyrotropin / Q000097:blood* / Q000235:genetics* / Q000378:metabolism; D013974:Thyroxine / Q000097:blood / Q000378:metabolism; D014284:Triiodothyronine / Q000097:blood / Q000378:metabolism; D000097564:Iodothyronine Deiodinase Type II
D020413:3' Untranslated Regions; D007453:Iodide Peroxidase; D009419:Nerve Tissue Proteins; D013972:Thyrotropin; D013974:Thyroxine; D014284:Triiodothyronine; D000097564:Iodothyronine Deiodinase Type II; C109812:iodothyronine deiodinase type I; C117274:iodothyronine deiodinase type III