Erythrocytes are hemolyzed by myeloperand triiodothyronine-dependent, but not oxidase, an H203-generating system (gluin the chloride-dependent, systems. Hemocose + glucose oxidase; hypoxanthine + lysis is inhibited by the peroxidase inxanthine oxidase) and an oxidizable cohibitors, azide and cyanide, and by catafactor (chloride, iodide, thyroxine, tnlase and is stimulated by superoxide iodothyr...

Introduction The magnitude of fall in thyroid hormone and rise in catecholamine levels are prognostic in critical illness (1, 2). These may be linked, as the amino acid tyrosine is converted by tyrosine hydroxylase to L-DOPA, and thence to dopamine, norepinephrine and epinephrine, whereas thyroxine (T4) and tri-iodothyronine (T3) are formed by the iodination of tyrosine residues in thyroglobuli...

OBJECTIVE Liver handling of thyroid hormones (TH) has been known to alter significantly during fasting. This study investigates whether renal handling of TH is also changed during fasting. METHODS We measured urinary excretion rates and clearances of free tri-iodothyronine (T(3)) and free thyroxine (T(4)) in healthy subjects prior to and on the third day of fasting. RESULTS During fasting, ...

The type I iodothyronine deiodinase (ID-I) of liver is an important enzyme for the conversion of the prohormone thyroxine (T4) to the active thyroid hormone 3,3',5-triiodothyronine (T3). Because it is an integral membrane protein of low abundance, purification of ID-I from rat liver has proven to be difficult. We have analyzed ID-I in liver microsomal fractions from various animals to reveal po...

Type II iodothyronine deiodinase (DII) messenger ribonucleic acid (mRNA) and its activity have been demonstrated in human normal brain. Although DII activity has been demonstrated in brain tumors, expression of DII mRNA has not been studied in these tumors. To investigate the mechanisms involved in the expression of DII activity in brain tumors, we studied DII mRNA and DII activity in astrocyto...

The biological activity of thyroid hormones (TH) is regulated by selenoenzymes of the iodothyronine deiodinase (DIO) family catalysing TH activating and inactivating reactions. Besides TH metabolism, several studies indicate an important role of DIO isoenzymes in tumorigenesis and cancer growth. It is therefore of therapeutic importance to identify modulators of DIO expression. We have synthesi...