J. Chehade et al., Age-related changes in the thyroid hormone effects on malondialdehyde-modified proteins in the rat heart, P SOC EXP M, 222(1), 1999, pp. 59-64
Citations number
39
Categorie Soggetti
Medical Research General Topics
Journal title
PROCEEDINGS OF THE SOCIETY FOR EXPERIMENTAL BIOLOGY AND MEDICINE
To determine the age-related changes in thyroid hormone (TH) effects on mal
ondialdehyde (MDA)-modified proteins in cardiac tissue, rats at 4, 12, and
25 months of age were studied, Hyperthyroidism was induced with daily injec
tion of L-triiodothyronine (15 mu g/100 g) intraperitoneally for 10 days. H
ypothyroidism was induced with 0.025% methimazole in the drinking water for
4 weeks, MDA proteins were measured with immunoblots using a specific anti
-MDA antiserum, MDA was measured as thiobarbituric acid reactive substance.
Hypothyroidism in 4-month-old rats was associated with significant reductio
n in MDA proteins compared to euthyroid rats (13.4 +/- 5.9% vs, 99.8 +/- 10
.4% of controls P < 0.001). Hyperthyroidism did not result in a significant
change of MDA proteins, In aged rats, neither hypothyroidism nor hyperthyr
oidism was associated with significant changes in cardiac MDA proteins, The
changes in MDA proteins did not correlate with cardiac MDA concentrations,
In young rats, the MDA concentrations (nmol/mg) were significantly reduced
in hypothyroidism (2.71 +/- 0.21) and were increased in hyperthyroidism (8
.19 +/- 0.78) compared to euthyroid values (5.06 +/- 0.71) P < 0.01. In age
d rats, cardiac MDA content was significantly increased during both hyperth
yroidism and hypothyroidism. We conclude that alterations in MDA protein co
ntent is yet another potential biochemical effect of TH in cardiac tissue.
This particular effect is significantly blunted with age,