Increased thyroid hormone production is essential for hatching of the chick and for the increased metabolism necessary for posthatch endothermic life. However, little is known about the ontogeny and distribution of pituitary thyrotrophs during this period or whether pituitary thyroid-stimulating hormone (TSH) production is regulated by endogenous thyroid hormones during chick embryonic developm...

the ideal approach for adequate management of subclinical hyperthyroidism (low levels of thyroid-stimulating hormone [tsh] and normal thyroid hormone level) is a matter of intense debate among endocrinologists. the prevalence of low serum tsh levels ranges between 0.5% in children and 15% in the elderly population. mild subclinical hyperthyroidism is more common than severe subclinical hyperthy...

We report a case of hyperthyroidism due to inappropriate thyrotrophin (TSH) secretion in a patient with selective pituitary resistance to thyroid hormone action. Symptoms of hyperthyroidism in patients with this disorder are usually mild, implying some peripheral tissue resistance to the metabolic effects of thyroid hormone. Our patient had unusually severe symptoms, including marked weight los...

Thymic hyperplasia is frequently observed in Graves' disease. However, detectable massive enlargement of the thymus is rare, and the mechanism of its formation has remained elusive. This case showed dynamic changes in thymic hyperplasia on serial computed tomography images consistent with changes in serum thyrotropin receptor (TSH-R) antibodies and thyroid hormone levels. Furthermore, the patie...

Central hypothyroidism (Central H) is mainly due to acquired lesions, either in the pituitary, the hypothalamus or both, and in such cases it is usually associated with deficient secretion of ther pituitary hormones. Isolated central hypothyroidism (I Central H) remains a very rare disease. By the use of the serum thyroid stimulating hormone (TSH) assay as an initial screening test for thyroid ...

The standard thyrotropin releasing hormone (TRH) test (200 μg) with synthetic TRH is no longer used commonly for the detection of primary hypothyroidism or hyperthyroidism. The reason has been that this test has been replaced by the development of more sensitive thyroid-stimulating hormone (TSH) assays, and hence suppression or elevation of TSH has been regarded as a sufficient criterion for th...

Patients with TSH-secreting pituitary tumors (TSHomas) have high serum TSH levels despite elevated thyroid hormone levels. The mechanism for this defect in the negative regulation of TSH secretion is not known. We performed RT-PCR to detect mutations in TRbeta from a surgically resected TSHoma. Analyses of the RT-PCR products revealed a 135-bp deletion within the sixth exon that encodes the lig...

Local thyroid hormone catabolism within the mediobasal hypothalamus (MBH) by thyroid hormone-activating (DIO2) and -inactivating (DIO3) enzymes regulates seasonal reproduction in birds and mammals. Recent functional genomics analysis in birds has shown that long days induce thyroid-stimulating hormone production in the pars tuberalis (PT) of the pituitary gland, which triggers DIO2 expression i...

congenital hypothyroidism is a condition of thyroid hormone deficiency. approximately 1 in 4000 newborn infants has a deficiency of thyroid function. the aim of this study is determination of the prevalence of permanent and transient congenital hypothyroidism (ch) in yazd, iran.from may 2006 to june 2008, 35377 newborns were screened by measuring serum tsh obtained by heel prick. the neonates w...

This study was designed to determine the effect of increase hyperthyrodisim on some hormones (Triiodothyronine, thyroxin, thyroid stimulating hormone) and biochemical parameters (creatinine, magnesium) 58 sample used in this at age (25-40 years), where samples were divided into two groups a rate 29 per group. The totals as follows: control group, group patients. It measured hormone Triiodothyro...