Total concentrations of thyroid hormones T(3) and T(4), and of their free forms, FT(3) and FT(4), D-aspartic acid (D-Asp), D-aspartate oxidase (D-AspO), D-aspartate racemase, H(2)O(2), and ROS (reactive oxygen species) were determined in rats and mice. T(3) and T(4) were 1 and 50 ng/ml, respectively, in serum, and 750 and 40000 ng/g, respectively, in thyroid. Concentrations of the free forms FT(3) and FT(4) were ca. 250 times lower than their respective total concentrations. The endogenous content of D-Asp in thyroid gland was ca. 100 nmol/g tissue, whereas the activity of D-AspO was ca. 80 units/mg thyroid, and that of D-aspartate racemase was ca. 15 units/mg thyroid. H(2)O(2) Concentration in rat and mouse thyroid gland was ca. 290 pmol/g thyroid, and the concentration of ROS was ca. 10 pmol/DCF/min/mg protein. H(2)O(2) is essential for the iodination of the tyrosyl residues to produce mono- and diiodotyrosine that are the precursors for the synthesis of T(3) and T(4). Production of H(2)O(2) in thyroid glands occurs by oxidation of endogenous D-Asp by D-AspO (D-Asp+O(2)+H(2)O-->alpha-oxaloacetate+NH(3)+H(2)O(2)). D-Aspartate racemase catalyzes the in vivo production of D-Asp from L-Asp. Thus, interaction of endogenous D-Asp, D-AspO, and D-aspartate racemase in thyroid gland constitutes an additional biochemical pathway for the production of H(2)O(2) and consequently for the synthesis of thyroid hormones.
Total concentrations of thyroid hormones T3 and T4, and of their free forms, FT3 and FT4, D-aspartic acid (D-Asp), D-aspartate oxidase (D-AspO), D-aspartate racemase, H2O 2, and ROS (reactive oxygen species) were determined in rats and mice. T3 and T4 were 1 and 50 ng/ml, respectively, in serum, and 750 and 40000 ng/g, respectively, in thyroid. Concentrations of the free forms FT3 and FT4 were ca. 250 times lower than their respective total concentrations. The endogenous content of D-Asp in thyroid gland was ca. 100 nmol/g tissue, whereas the activity of D-AspO was ca. 80 units/mg thyroid, and that of D-aspartate racemase was ca. 15 units/mg thyroid. H2O2 Concentration in rat and mouse thyroid gland was ca. 290 pmol/g thyroid, and the concentration of ROS was ca. 10 pmol/DCF/min/mg protein. H2O2 is essential for the iodination of the tyrosyl residues to produce mono- and diiodotyrosine that are the precursors for the synthesis of T3 and T4. Production of H 2O2 in thyroid glands occurs by oxidation of endogenous D-Asp by D-AspO (D-Asp+O2+H2O→α-oxaloacetate + NH3+H2O2). D-Aspartate race-mase catalyzes the in vivo production of D-Asp from L-Asp. Thus, interaction of endogenous D-Asp, D-AspO, and D-aspartate racemase in thyroid gland constitutes an additional biochemical pathway for the production of H2O2 and consequently for the synthesis of thyroid hormones. © 2010 Verlag Helvetica Chimica Acta AG.
Thyroid hormones and D-aspartic acid, D-aspartate oxidase, D-aspartate racemase, H2O2, and ROS in rats and mice
USIELLO, Alessandro;
2010
Abstract
Total concentrations of thyroid hormones T3 and T4, and of their free forms, FT3 and FT4, D-aspartic acid (D-Asp), D-aspartate oxidase (D-AspO), D-aspartate racemase, H2O 2, and ROS (reactive oxygen species) were determined in rats and mice. T3 and T4 were 1 and 50 ng/ml, respectively, in serum, and 750 and 40000 ng/g, respectively, in thyroid. Concentrations of the free forms FT3 and FT4 were ca. 250 times lower than their respective total concentrations. The endogenous content of D-Asp in thyroid gland was ca. 100 nmol/g tissue, whereas the activity of D-AspO was ca. 80 units/mg thyroid, and that of D-aspartate racemase was ca. 15 units/mg thyroid. H2O2 Concentration in rat and mouse thyroid gland was ca. 290 pmol/g thyroid, and the concentration of ROS was ca. 10 pmol/DCF/min/mg protein. H2O2 is essential for the iodination of the tyrosyl residues to produce mono- and diiodotyrosine that are the precursors for the synthesis of T3 and T4. Production of H 2O2 in thyroid glands occurs by oxidation of endogenous D-Asp by D-AspO (D-Asp+O2+H2O→α-oxaloacetate + NH3+H2O2). D-Aspartate race-mase catalyzes the in vivo production of D-Asp from L-Asp. Thus, interaction of endogenous D-Asp, D-AspO, and D-aspartate racemase in thyroid gland constitutes an additional biochemical pathway for the production of H2O2 and consequently for the synthesis of thyroid hormones. © 2010 Verlag Helvetica Chimica Acta AG.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
