We evaluated the effects of temperature and humidity on thyroid hormones (T4, T3) and thyrotropin (TSH) measured in blood spots dried on filter paper. RIAs for T4 and T3 blood spots were optimized to measure these analytes over the neonatal and euthyroid adult reference intervals. Sensitivities of the T3 and T4 assays were 0.5 and 10 nmol/L, respectively. A blood-spot immunoradiometric assay fo...

The present study was undertaken to define the source of endogenous triiodothyronine (T3) production responsible for maintaining serum T3 levels in euthyroid subjects with depressed serum thyroxine (T4) values. After withdrawal from 4 wk of exogenous T3 administration, a 22% decline in serum T3 values (from 129 +/- 6 to 99 +/- 4 ng/dl) was observed in six euthyroid subjects, despite a twofold r...

AIM The aim of the present study was to generate baseline data on the normal values of the thyroidhormone (TH) activity as well as their correlation with age and season. MATERIALS AND METHODS Blood samples (10 ml) were collected from jugular vein of 30 female mithun's of three different age groups viz. Calves (6 months to 1 year), heifer (1-3 years) and adult (above 3 years) during the three ...

CONTEXT Levothyroxine (LT4) monotherapy is the standard of care for hypothyroidism. OBJECTIVE To determine whether LT4 at doses that normalize the serum TSH is associated with normal markers of thyroid status. DESIGN Cross-sectional data from the US National Health and Nutrition Examination Survey (2001-2012) was used to evaluate 52 clinical parameters. LT4 users were compared to healthy co...

The effects of anaesthesia on serum thyroid hormones were studied in 32 pregnant young women undergoing Caesarean section at term. Eighteen patients received general anaesthesia and 14 lumbar extradural blockade. Maternal serum concentrations of thyrotrophin (TSH), thyroxine (T4), triiodothyronine (T3) and reverse triiodothyronine (rT3) were measured using radioimmunoassay at 0, delivery and 24...

CONTEXT Thyroidal production of triiodothyronine (T3) is absent in athyreotic patients, leading to the suggestion that T3 deficiency may be unavoidable during levothyroxine (LT4) therapy. However, trials evaluating therapy with combined LT4 and T3 have failed to demonstrate any consistent advantage of combination therapy. OBJECTIVE To determine whether T3 levels in patients treated with LT4 t...

A case of transient hyperthyrotropinaemia was found by mass screening for neonatal hypothyroidism using the paired TSH assay method. The patient was a baby boy born at term after a normal pregnancy who grew without any abnormal signs or symptoms. For the first 7 months after birth, his serum TSH was abnormally high while his total serum T4, T3, and free T4, T3 were within normal limits, exept f...

In total, 240 studies including serum T4, T3, TSH and thyroid uptake at 2 and 24 hrs were performed in 48 Bangladeshi adult individuals (52% female and 48% male). The aim of the present study was to make a correlation between thyroid serum levels and radioiodine thyroid uptake values of same individuals. Serum T4 and T3 were assessed with commercially available radioimmunoassay kits and TSH wit...

Patients with resistance to thyroid hormone (RTH) exhibit elevated thyroid hormone levels and inappropriate thyrotropin (thyroid-stimulating hormone, or TSH) production. The molecular basis of this disorder resides in the dominant inhibition of endogenous thyroid hormone receptors (TRs) by a mutant receptor. To determine the relative contributions of pituitary versus hypothalamic resistance to ...