Effect of triiodothyronine on reactive oxygen species generation by leukocytes, indices of oxidative damage, and antioxidant reserve.
We have examined the effect of short-term triiodothyronine (T3) administration on reactive oxygen species (ROS) generation by leukocytes in 9 euthyroid subjects. At a dose of 60 microg/d orally for 7 days, T3 induced a significant increase in ROS generation by mononuclear cells (MNCs) from 183 +/- 102 mV at baseline to 313 +/- 111 mV on the seventh day (P < .02), and by polymorphonuclear leukocytes (PMNLs) from 195 +/- 94 mV at baseline to 302 +/- 104 mV on the seventh day (P < .02). There was also a significant increase in meta-tyrosine (P < .001) and ortho-tyrosine (P < .001), known indices of oxidative damage to proteins and amino acids. However, there was no increase in plasma thiobarbituric acid-reactive substances (TBARS), an index of oxidative damage to lipids, and in the level of carbonylated proteins, a less sensitive index to assess protein oxidation. There was no decrease in the level of antioxidants such as alpha-tocopherol, vitamin A, beta-carotene, lycopene, and lutein/zeaxanthin. The stimulatory effect on ROS generation may reflect a generalized increase in metabolic activity or may be a specific effect on NADPH oxidase in leukocyte membranes. The absence of a significant change in TBARS, carbonylated proteins, alpha-tocopherol, vitamin A, beta-carotene, lycopene, and lutein/zeaxanthin may reflect the short duration of the increased ROS load.
Magsino
C H
CH
Department of Medicine, State University of New York at Buffalo, USA.
Hamouda
W
W
Ghanim
H
H
Browne
R
R
Aljada
A
A
Dandona
P
P
D000328:Adult; D000975:Antioxidants / Q000378:metabolism*; D005260:Female; D006801:Humans; D007962:Leukocytes / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D019255:NADPH Oxidases / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D013960:Thyroid Function Tests; D014284:Triiodothyronine / Q000494:pharmacology*; D014443:Tyrosine / Q000378:metabolism
D000975:Antioxidants; D017382:Reactive Oxygen Species; D017392:Thiobarbituric Acid Reactive Substances; D014284:Triiodothyronine; D014443:Tyrosine; C026741:2-tyrosine; C015566:3-tyrosine; D019255:NADPH Oxidases