Disturbance of thyroidal iodine metabolism in BB/W rat.
To investigate the thyroid function in Bio-Breeding Worcester (BB/W) rats, we have examined the iodine metabolism, serum TSH and thyroid hormone levels in 8- and 16-week-old BB/W and normal Wistar (W) rats. At 8 weeks of age, serum TSH levels were significantly higher in BB/W rats than in W rats, although there was no difference in the serum levels of free T3 and free T4. Furthermore, the thyroidal radioactive iodine incorporation at 48 h was significantly lower in BB/W rats, suggesting that they might have some defects in iodine organification. At 16 weeks of age, serum TSH levels were also significantly higher in BB/W rats than in W rats. Furthermore, serum TSH levels in 16-week-old BB/W rats were significantly higher than in 8-week-old BB/W rats. The thyroid weight was significantly greater in BB/W rats, probably due to the increased serum TSH. The thyroidal radioactive iodine uptake at 48 h and the iodine content in the thyroid homogenates were significantly lower in BB/W rats. These results suggest that BB/W rats have some defect in iodine metabolism resulting in impaired thyroid hormone synthesis.
Miura
S
S
Fourth Department of Internal Medicine, Saitama Medical School, Japan.
Hara
Y
Y
Iitaka
M
M
Fukasawa
N
N
Hase
K
K
Urabe
M
M
Sakatsume
Y
Y
Yanagisawa
M
M
Ishii
J
J
Kawazu
S
S
D000818:Animals; D007455:Iodine / Q000032:analysis / Q000378:metabolism* / Q000493:pharmacokinetics; D007457:Iodine Radioisotopes; D009929:Organ Size; D011863:Radioimmunoassay; D051381:Rats; D011913:Rats, Inbred BB; D011919:Rats, Inbred Strains; D013961:Thyroid Gland / Q000033:anatomy & histology / Q000737:chemistry / Q000378:metabolism*; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
D007457:Iodine Radioisotopes; D014284:Triiodothyronine; D013972:Thyrotropin; D007455:Iodine; D013974:Thyroxine