One agent used by ophthalmologists to aid in funduscopic examinations is sodium fluorescein (“Funduscein,” Cooper Vision). We recently received a patient’s specimen for measurement of thyroxin (T4) and T3-uptake, drawn one day after she had been examined by an ophthalmologist. Owing to the high background fluorescence (62 580 arb.units) and low background polarization (24 mPol), no results were...

Triiodothyron me (T3)-upta ke values in selected human serum pools were compared by use of Abbott’s “Trisorb,” Mallinckrodt Nuclear’s “Res0-Mat,” Curtis Nuclear’s “Tri-lonex,” and a standard procedure. In addition, interlaboratory variation was measured among laboratories using the Abbott and Mallinckrodt procedures. Study of methodological variables indicated that incubation time and temperatu...

Thyroid hormones [predominantly 3,5,3'-triiodo-L-thyronine (T3)] regulate cholesterol and lipoprotein metabolism, but cardiac effects restrict their use as hypolipidemic drugs. T3 binds to thyroid hormone receptors (TRs) alpha and beta. TRbeta is the predominant isoform in liver, whereas T3 effects on heart rate are mediated mostly by TRalpha. Drugs that target TRbeta or exhibit tissue-selectiv...

We examined the effect of endogenous free fatty acids (FFA) on the measurement of free thyroxin (FT4) by five different methodologies represented in 16 different assays in a large number of patients with nonthyroidal illness (NTI). Some, but not all, one-step (analog) FT4 RIAs negatively correlated with FFA concentration. All two-step FT4 RIAs, equilibrium dialysis FT4, and the dialyzable (free...

Iodine plays a central role in thyroid physiology, being both a major constituent of thyroid hormones (THS) and a regulator of thyroid gland function. This review concerns those aspects of thyroid physiology in which significant advances have been made in recent years. We have known for decades that the thyroid gland concentrates iodine (I-) against an electrochemical gradient by a carrier-medi...

We tested the hypothesis considering the role of hypothalamic-pituitary-thyroid axis (HPT), L-triiodothyronine (L-T3) uptake into erythrocytes, and the role of membrane lipids in the development and treatment of affective disorders. Changes in kinetic parameters (V(max), maximal velocity and K(M), apparent Michaelis constant) of L-T3 uptake into red blood cells (RBCs) and changes in membrane fl...

The synthetic flavonoids EMD 23188 and EMD 49209, developed as T4 analogs, displace T4 from transthyretin, and in vitro they inhibit 5'-deiodinase activity. In vivo EMD 21388 causes tissue-specific changes in thyroid hormone metabolism. In tissues that are dependent on T3 locally produced from T4, total T3 was diminished. It was not known whether it was the presence of EMD interfering with 5'-d...

Thyroid gland is an essential endocrine that present in the human body. This review highlights production, regulation and disease conditions of thyroid hormones. The controlled with help hypothalamus pituitary brain. production hormones involves five main steps such synthesis thyroglobulin (TG), iodide uptake, iodination thyroglobulin, storage release. two important produced by are Thyroxine (T...

Previous studies have demonstrated that short-term oral iodide administration, in doses ranging from 1500 micrograms to 250 mg/day, has an inhibitory effect on thyroid hormone secretion in normal men. As iodide intake in the USA may be as high as 800 micrograms/d, we investigated the effects of very low dose iodide supplementation on thyroid function. Thirty normal men aged 22-40 years were ran...