To determine which genes are regulated by thyroid stimulating hormone (thyrotropin, TSH), insulin and insulin-like growth factor-1 (IGF-1) in the rat thyroid, we used the microarray technology and observed the changes in gene expression. The expressions of genes for bone morphogenetic protein 6, the glucagon receptor, and cyclin D1 were increased by both TSH and IGF-1; for cytochrome P450, 2c37, the expression was decreased by both. Genes for cholecystokinin, glucuronidase, beta, demethyl-Q 7, and cytochrome c oxidase, subunit VIIIa, were up-regulated; the genes for ribosomal protein L37 and ribosomal protein L4 were down-regulated by TSH and insulin. However, there was no gene observed to be regulated by all three: TSH, IGF-1, and insulin molecules studied. These findings suggest that TSH, IGF-1, and insulin stimulate different signal pathways, which can interact with one another to regulate the proliferation of thyrocytes, and thereby provide additional influence on the process of cellular proliferation.
Animals ; Bone Morphogenetic Protein 6 ; Bone Morphogenetic Proteins/biosynthesis ; Cell Line, Tumor ; Cyclin D1/biosynthesis ; *Gene Expression Profiling ; *Gene Expression Regulation ; Insulin/*biosynthesis/metabolism ; Insulin-Like Growth Factor I/*biosynthesis ; Models, Genetic ; *Oligonucleotide Array Sequence Analysis ; Rats ; Receptors, Glucagon/biosynthesis ; Thyroid Gland/*metabolism ; Thyrotropin/*biosynthesis/metabolism ; Time Factors

We evaluated the efficacy of recombinant human thyroid-stimulating hormone (rhTSH) versus thyroid hormone withdrawal (THW) prior to radioiodine remnant ablation (RRA) in thyroid cancer. A systematic search of MEDLINE, EMBASE, the Cochrane Library, and SCOPUS was performed. Randomized controlled trials that compared ablation success between rhTSH and THW at 6 to 12 months following RRA were included in this study. Six trials with a total of 1,660 patients were included. When ablation success was defined as a thyroglobulin (Tg) cutoff of 1 ng/mL (risk ratio, 0.99; 95% confidence interval, 0.96-1.03) or a Tg cutoff of 1 ng/mL plus imaging modality (RR 0.97; 0.90-1.05), the results of rhTSH and THW were similar. There were no significant differences when ablation success was defined as a Tg cutoff of 2 ng/mL (RR 1.03; 0.95-1.11) or a Tg cutoff of 2 ng/mL plus imaging modality (RR 1.02; 0.95-1.09). When a negative 131I-whole body scan was used solely as the definition of ablation success, the effects of rhTSH and THW were not significantly different (RR 0.97; 0.93-1.02). Therefore, ablation success rates are comparable when RRA is prepared by either rhTSH or THW.
Catheter Ablation ; Clinical Trials as Topic ; Databases, Factual ; Humans ; Iodine Radioisotopes/*therapeutic use ; Radiopharmaceuticals/*therapeutic use ; Recombinant Proteins/biosynthesis/genetics/therapeutic use ; Risk ; Thyroglobulin/analysis/metabolism ; Thyroid Neoplasms/*drug therapy/ultrasonography ; Thyrotropin/genetics/metabolism/*therapeutic use ; Treatment Outcome ; Whole Body Imaging

The aim of the present study was to evaluate plasma total homocysteine (Hcys) and serum fibrinogen concentrations in subclinical hypothyroid (SH) and overt hypothyroid patients before and after L-thyroxine (LT4) replacement and to compare them in euthyroid subjects. Fifteen SH and 20 hypothyroid premenopausal women were recruited in the study. We measured fasting plasma levels of Hcys and serum levels of free thyroxine (fT4), free triiodothyronine (fT3), thyrotropin (TSH), folate, vitamin B12, fibrinogen, renal functions, and lipid profiles in patients with SH and overt hypothyroid patients before and after LT4 treatment. Eleven healthy women were included in the study as a control group. Pretreatment Hcys levels were similar in SH and control subjects, whereas mean fibrinogen level of SH patients was higher than that of control subjects (p<0.05). Baseline Hcys (p<0.01) and fibrinogen (p<0.001) levels of the overt hypothyroid patients were significantly higher than those of the healthy subjects, and the pretreatment Hcys levels decreased with LT4 treatment (p<0.001). In conclusion, our data support that SH is not associated with hyperhomocysteinemia and Hcys does not appear to contribute to the increased risk for atherosclerotic disease in patients with SH.
Adult ; Case-Control Studies ; Female ; Fibrinogen/biosynthesis ; Folic Acid/blood ; Homocysteine/*blood ; Humans ; Hypothyroidism/*blood/*diagnosis ; Kidney/metabolism ; Middle Aged ; Thyrotropin/blood ; Thyroxine/*blood ; Triiodothyronine/blood ; Vitamin B 12/blood

OBJECTIVETo observe the effect of overdose iodine on the expression of CCK gene in brains of rats and identify the possible mechanisms.

METHODSOne-month weaning Wistar rats were randomly divided into five groups which were fed with normal feedstuff and water supplemented with different concentrations of potassium iodide, named A group (iodine ration was about 6.15 microg per day), B group (iodine ration was about 30.75 microg per day), C group (iodine ration was about 61.5 microg per day), D group (iodine ration was about 307.5 microg per day) and E group (iodine ration was about 615 microg per day). Rats were sacrificed after being fed for three or six months. Then serum thyroid hormones were measured by radioimmunoassay and the mRNA level of CCK gene was studied by using RT-PCR technique.

RESULTSAt the end of three months, the values of thyroid hormones in E group [TT4 (45.2 +/- 13.7) nmol/L, TI'3 (0.65 +/- 0.20) nmol/L, FT3 (0.93 +/- 0.45) pmol/L, FT4 (7.07 +/- 2.43) pmol/L, rT3 (0.15 +/- 0.04) nmol/L] were all lower than those in A group [TT4 (76.0 +/- 18.8) nmol/L, TT3 (1.34 +/- 0.41) nmol/L, FT3 (2.45 +/- 0.62) pmol/L, FT4 (15.12 +/- 3.40) pmol/L, rT3 (0.24 +/- 0.04) nmol/L]. There were significant differences between E group and A group on the levels of serum TH (F values are 14.68, 16.03, 21.16, 20.25, 13.52 respectively, P < 0.01); FT3 levels in C and D groups were significantly decreased as compared to A and B groups (F = 21.16, P < 0.05). rT3 level in D group was significantly decreased compared with A,B and C groups (F = 13.52, P < 0.05). At the end of six months, the levels of serum TH in E group (TT4 (51.84 +/- 15.83) nmol/L, TT3 (0.77 +/- 0.22) nmol/L, FT4 (6.88 +/- 2.23) pmol/L, FT3 (0.74 +/- 0.28) pmol/L, rT3 (0.14 +/- 0.03) nmol/L) were lower than those in any other groups (F values were 6.05, 12.22, 11.25, 13.42, 5.89 respectively, P < 0.05). At the end of both three and six months, the mRNA levels of CCK gene in E group were lower than any other groups (F values were 4.04, 3.95 respectively, P < 0.01). The results of correlation analysis showed that serum FT4 had linear correlation with levels of CCK mRNA (r values were 0.990, 0.948 respectively; P < 0.05); However serum FT3 had no linear correlation with the levels of CCK mRNA (r values are 0.970, 0.932 respectively).

CONCLUSIONSExposure to overdose of iodine (iodine ration was 100-fold higher than that of A group) could decrease the mRNA level of CCK gene. Compared with FT3, FT4 might have more important role on the regulation of CCK mRNA induced by excess of iodine.

Animals ; Brain ; metabolism ; Cholecystokinin ; biosynthesis ; genetics ; Drug Overdose ; Female ; Food, Formulated ; Gene Expression ; Hyperphagia ; Iodine ; toxicity ; Male ; RNA, Messenger ; genetics ; Rats ; Rats, Wistar ; Thyroid Hormones ; blood ; Thyrotropin ; blood ; Thyroxine ; blood ; Triiodothyronine ; blood