OBJECTIVEThe inactivating mutation of thyrotropin receptor (TSHR) gene results in partial or complete insensitivity of thyrotropin (TSH) and dysfunction of the TSH-TSHR-cAMP cascade. Therefore, it may cause congenital hypothyroidism (CH). Depending on the degree of impairment of TSHR function, patients can present with subclinical hypothyroidism at one extreme of the spectrum, or severe hypothyroidism at the other. This study aimed to understand the relation between inactivating mutations of TSHR gene and Chinese children with CH.

METHODS(1) Seventy-nine Chinese children with CH, including 14 subclinical hypothyroidism patients (8 boys and 6 girls, age 1 - 5.5 years) and 65 hypothyroidism patients (27 boys and 38 girls, age 1.5 - 6 years) were enrolled in this study. Meanwhile, 100 normal children were enrolled as control, 40 were male and 60 were female. The age of the normal children were at a range of 1 - 8 years. (2) Total genomic DNA was extracted from peripheral blood leukocytes of the 79 patients and 100 normal subjects. Exons 1 - 10 of TSHR gene were individually amplified by polymerase chain reaction (PCR) and mutations were detected by direct sequencing.

RESULTS(1) A compound heterozygous missense mutations (Pro52Thr/Val689Gly) and a heterozygous missense mutation (Gly245Ser) were detected in 79 patients. The mutations of Pro52Thr and Gly245Ser were located within the extracellular domain of TSHR, while Val689Gly was located within the intracellular domain of TSHR. In 30 patients the normal cytosine at position 2181 in exon 10 was replaced by a guanine (GAC-->GAG), resulting in the replacement of Glu(727) by Asp. In 47 patients, the normal thymidine at position 561 in exon 7 was replaced by a cytosine (AAT-->AAC). This substitution did not change the amino acid (Asn) at position 187. (2) In 33 normal children the normal cytosine at position 2181 in exon 10 was also replaced by a guanine (GAC-->GAG) and in 50 normal children the normal thymidine at position 561 in exon 7 was replaced by a cytosine (AAT-->AAC).

CONCLUSIONSThree heterozygous missense mutations (Pro52Thr, Gly245Ser, Val689Gly) of TSHR gene were firstly detected in Chinese children with CH. There was a polymorphism in exon 10 at nucleotide 2181 (GAC-->GAG) and in exon 7 at nucleotide 561 (AAT-->AAC) in TSHR gene. The inactivating mutation of TSHR gene is an infrequent pathogeny for CH.

Amino Acid Substitution ; genetics ; Asian Continental Ancestry Group ; Child ; Congenital Hypothyroidism ; genetics ; DNA ; analysis ; Exons ; genetics ; Female ; Gene Silencing ; Genes, gag ; genetics ; Humans ; Hypothyroidism ; genetics ; Male ; Mutation ; Mutation, Missense ; genetics ; Polymorphism, Genetic ; genetics ; Receptors, Thyrotropin ; metabolism ; Thyrotropin ; genetics

OBJECTIVETo investigate the expression regulation of thyrotrophin-releasing hormone (TRH) and TRH receptor (TRH-R), and their role in the development of rat testis.

METHODSOligonucleotide primers were designed from the sequences of rat hypothalamus prepro TRH (ppTRH) and pituitary TRH-R cDNA for reverse transcription polymerase chain reaction (RT-PCR). Specific fragments of ppTRH and TRH-R cDNA were cloned and sequenced. Expression plasmids containing ppTRH and TRH-R genes were then constructed, and expression was found in E. coli DH5-alpha. ppTRH and TRH-R mRNA in the testis was quantitated in RNA samples prepared from rats at different developmental stages by real time quantitative RT-PCR.

RESULTSThe quantitative analyses demonstrated that no ppTRH and TRH mRNA could be detected at the earliest stage (day 8). ppTRH and TRH mRNA signals were detected on day 15 and increased progressively on days 20, 35, 60 and 90.

CONCLUSIONOur results suggest that rat testis could specifically express TRH and TRH-R, and the transcriptions of ppTRH and TRH-R genes in the rat testis were development-dependent. The acquirement of expressed products for ppTRH and TRH-R can be used for further research on the physiological significance of TRH and TRH-R expression in rat testis.

Age Factors ; Animals ; Male ; Protein Precursors ; genetics ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley ; Receptors, Thyrotropin-Releasing Hormone ; genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Testis ; growth & development ; metabolism ; Thyrotropin-Releasing Hormone ; genetics

BACKGROUND/AIMS: Graves' disease (GD) is caused by thyroid-stimulating hormone receptor (TSHR) and thyroid-stimulating immunoglobulin (TSI). We used a recently introduced, technically enhanced TSI bioassay to assess its diagnostic value and determine the cut-off in patients in high iodine intake area. METHODS: In a cross-sectional setting, we collected serum from 67 patients with untreated GD, 130 with GD under treatment, 22 with GD in remission, 42 with Hashimoto's thyroiditis, 12 with subacute thyroiditis, 20 with postpartum thyroiditis, and 93 euthyroid controls. TSI was measured using the Thyretaintrade mark bioassay, which is based on Chinese hamster ovary cells transfected with chimeric TSHR (Mc4). TSI levels are reported as a specimen-to-reference ratio percentage (SRR%). RESULTS: The TSI levels in patients with GD (either treated or not) were significantly higher than those of the remaining patients (p < 0.05). The new bioassay showed a sensitivity of 97.0% and a specificity of 95.9% with a cut-off value of 123.0 SRR% for GD. A weak correlation was found between TSI and thyrotropin-binding inhibiting immunoglobulin (TBII) (rs = 0.259, p = 0.03), but no correlation was found between TSI and tri-iodothyronine or free thyroxine. CONCLUSIONS: The Mc4-CHO bioassay showed comparable diagnostic value for GD with the conventional TBII assay. We propose a cut-off of 123.0 SRR% in areas where iodine intake is high.
Adult ; Animals ; *Biological Assay ; Biological Markers/blood ; CHO Cells ; Case-Control Studies ; Cricetinae ; Cricetulus ; Cross-Sectional Studies ; Female ; Genes, Reporter ; Graves Disease/*diagnosis/immunology/therapy ; Hashimoto Disease/diagnosis ; Humans ; Immunoglobulins, Thyroid-Stimulating/*blood ; Luciferases/genetics/metabolism ; Male ; Middle Aged ; Postpartum Thyroiditis/diagnosis ; Predictive Value of Tests ; Protein Binding ; Radioimmunoassay ; Receptors, Thyrotropin/genetics/*metabolism ; Recombinant Fusion Proteins/metabolism ; Republic of Korea ; Sensitivity and Specificity ; Thyroiditis, Subacute/diagnosis ; Transfection

OBJECTIVETo observe the effects of amitrole on the transcription of thyroglobulin (tg), thyroid peroxidase (tpo), Na(+)/I- symporter (nis), Na(+)/I- symporter (nis), thyroid-stimulating hormone receptor (tshr), thyroid transcription factor 1 (ttf-1) and paired-domain protein-8 (pax-8) genes in FRTL-5 cells and investigate the mechanism of amitrole for intervening in thyroid hormone activity.

METHODSFRTL-5 cells were treated with amitrole at 0.001, 0.01 and 0.1 mg/ml for 24 h, respectively, after which the cells were collected for extraction of the total RNA. RT-PCR was used to examine the effects of amitrole on the transcription of tg, tpo, nis, tshr, pax-8 and ttf-1 genes in FRTL-5 cells.

RESULTSAmitrole significantly induced tg gene transcription at all the doses, but produced no obvious effects on tpo and nis gene transcription. At the concentration of 0.1 mg/ml, amitrole significantly reduced pax-8 and tshr gene transcription but increased ttf-1 gene transcription.

CONCLUSIONThe effects of amitrole on thyroid hormone activity may be related with its actions on tg, ttf-1, tshr and pax-8 gene transcription.

Amitrole ; toxicity ; Animals ; Cells, Cultured ; Enzyme Inhibitors ; toxicity ; Epithelial Cells ; cytology ; drug effects ; metabolism ; Nuclear Proteins ; genetics ; Rats ; Rats, Inbred F344 ; Receptors, Thyrotropin ; genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Thyroglobulin ; genetics ; Thyroid Gland ; cytology ; Thyroid Nuclear Factor 1 ; Transcription Factors ; genetics ; Transcription, Genetic ; drug effects