Background: Smoking can cause thyroid disorders; the aim of the present study was to investigate the association between smoking status and changes in thyroid hormone levels among adult males during a decade long follow-up of in the Tehran Thyroid Study (TTS). Methods: Data of 895 adult males (smokers=115, non-smokers=691, ex-smokers=89) participants of the TTS without any previously known thy...

A number of thyroid function tests have recently been developed in which components of the hypothalamic-pituitary-thyroid axis are directly measured; these include estimation of the total concentrations of the thyroid hormones, thyroxine (T4) and tri-iodothyronine (T3), their free (unbound) fractions, the thyroid hormone-binding proteins, and the serum TSH (thyroid-stimulating hormone, thyrotro...

Resistance to thyroid hormone (RTH) is a dominantly inherited condition of impaired tissue responsiveness to thyroid hormone (TH). Of variable severity, the presence of goiter, tachycardia, hyperactivity, or abnormal findings on routine laboratory tests usually lead to further investigation and, ultimately, the diagnosis of RTH. Characteristic thyroid function tests are elevated free thyroxine ...

Seventy-eight clinically euthyroid patients with atrial dysrhythmias, either established or paroxysmal, and sixty-three patients in sinus rhythm with coronary disease were screened for hyperthyroidism using thyroid function tests including the thyroid-stimulating hormone (TSH) response to thyrotrophin-releasing hormone (TRH). All had normal levels of serum thyroxine (T4) apart from three with d...

The thyroid hormones (THs) L-thyroxine (T4) and L-triiodothyronine (T3) have a profound influence on the development and maturation of the mammalian brain, both before and after birth. Any impairment in the supply of THs to the developing nervous system leads to severe and irreversible changes in both the overall architecture and functions of the brain and causes, in humans, neurological and mo...

Purpose: To analyze whether the thyroid status is affecting in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) outcomes. Methods: In this retrospective cohort study, we reviewed the medical records of 426 infertile women who underwent IVF/ICSI cycles. Included were hypothyroid (HypoT-LT4) patients with serum thyroidstimulating hormone (TSH) concentrations > 4.0 μIU/mL, which wer...

To evaluate the effect of perinatal factors and sampling methods on thyroid stimulating hormone (TSH) and thyroid hormone levels in cord blood, serum TSH, free thyroxine (FT4) and free triiodothyronine (FT3) concentrations were measured in 124 healthy term neonates. Eighty-eight infants were born in normal vaginal deliveries, 25 were delivered by vacuum extractor and 11 by Cesarean section. The...

This issue of Clinical Chemistry contains 3 reports from the IFCC Working Group for Standardization of Thyroid Function Tests. The first report relates to thyroidstimulating hormone (TSH) (1 ), the second addresses free thyroxine (FT4) and free triiodothyronine (FT3) (2 ), and the third discusses total thyroxine (T4) and total triiodothyronine (T3) (3 ). Each of these reports is authored by a g...

In seasonal animals, photoperiod exerts profound effects on physiology, such as growth, energy balance and reproduction, via changes in the neuroendocrine axes. A key element of the photoperiodic response is the thyroid hormone level in the hypothalamus, which is controlled via retrograde transport of thyroid-stimulating hormone (TSH) from the pars tuberalis of the pituitary. TSH regulates type...

A patient is described in whom thyroid binding globulin (TBG) excess was found in association with a pituitary macroadenoma containing thyroid stimulating hormone (TSH)-producing cells, and the potential for diagnostic confusion arising from this unusual combination of endocrine disorders is discussed. The patient presented with visual field disturbance, and magnetic resonance imaging led to th...