Serum paraoxonase 1 activity is decreased in thyroid dysfunction.
Changes in serum lipid and lipoprotein concentrations occur frequently in disorders of thyroid function. LDL-cholesterol (LDL-C) oxidation susceptibility is higher in these patients than in normal population. This study aims at assessing lipids, lipoproteins, apolipoproteins and serum paraoxonase 1 (PON1) activity in patients with thyroid dysfunction. Ninety-nine patients with thyroid dysfunction, (49 hypothyroid and 50 hyperthyroid) were compared with 2 separately age- and sex-matched control groups. A fasting blood sample was obtained and serum total cholesterol, triglycerides, apolipoproteins A-I and B, and PON1 activity were measured. In hyperthyroid patients, significantly lower PON1 activity (45 +/- 23 vs 67 +/- 37 IU/ml, p<0.001), triglycerides (112 +/- 53 vs 166 +/- 130 mg/dl, p<0.05), apolipoprotein A-I (137 +/- 26 vs 154 +/- 21 mg/dl, p<0.001) and apolipoprotein B (75 +/- 18 vs 86 +/- 25 mg/dl, p<0.05) were found. Hypothyroid patients had lower PON1 activity (46 +/- 21 vs 64 +/- 32 IU/ml, p<0.005) compared with controls, and higher total cholesterol (224 +/- 69 vs 185 +/- 41 mg/dl, p<0.001), LDL-C (133 +/- 59 vs 93 +/- 36 mg/dl, p<0.001), and apolipoprotein B (107 +/- 37 vs 84 +/- 23 mg/dl, p<0.001). The results show significant changes of lipid levels in thyroid dysfunction. In addition, a significant reduction in PON1 activity was observed in both hyper- and hypothyroid patients. Increased LDL-C oxidation in thyroid dysfunction observed in other studies, at least to some extent, can be attributed to reduced PON1 activity.
Azizi
F
F
Endocrine Research Center, Shaheed Beheshti University of Medical Sciences, Tehran, Iran. Azizi@erc-iran.com
Raiszadeh
F
F
Solati
M
M
Etemadi
A
A
Rahmani
M
M
Arabi
M
M
D000328:Adult; D001053:Apolipoproteins / Q000097:blood; D043303:Aryldialkylphosphatase / Q000097:blood*; D005260:Female; D006801:Humans; D006980:Hyperthyroidism / Q000097:blood / Q000201:enzymology; D007037:Hypothyroidism / Q000097:blood / Q000201:enzymology; D008055:Lipids / Q000097:blood; D008074:Lipoproteins / Q000097:blood; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D012907:Smoking / Q000378:metabolism; D013959:Thyroid Diseases / Q000097:blood* / Q000201:enzymology*; D013960:Thyroid Function Tests; D013963:Thyroid Hormones / Q000097:blood
D001053:Apolipoproteins; D008055:Lipids; D008074:Lipoproteins; D013963:Thyroid Hormones; D043303:Aryldialkylphosphatase; C468406:PON1 protein, human