Lipid profiles and apolipoprotein concentrations were measured in 34 premenopausal women with hypothyroidism, before and after 3 months of 1-thyroxine therapy. 17 patients who had elevated serum TSH level but normal total T3 and free. T4 index
were
classifed into subclinical hypothyroidism (SCH), and another 17 with elevated TSH and low free T4 index or low total T3 were classified as overt hypothyroidism (OH). These groups were compare with 25 euthyroid women matched for age and body mass
index.
Before treatment, serum total cholesterol (TC), triglyceride (TG), and LDL-cholesterol (LDL-C) were significantly elevated in OH. All of those parameters decreased significantly after treatment, with normalization of TC and LDL-C. HDL-cholesterol
(HDL-C) level was not different in OH from control value, also showing no change with treatment. Serum apolipoprotein A-I (Apo A-I), and apolipoprotein B (Apo B) were also significantly elevated in OH, and returned to normal levels with thyroxine
therapy. In SCH, pretreatment TC, TG, HDL-, and LDL-C were not different compared with control. However, TC, LDL-C decreased significantly after thyroxine treatment. TG and HDL-C did not show any measurable changes. Serum Apo A-I lvel was not
different
from control and showed no significant changes, however, Apo B level was elevated in SCH which returned to control value with thyroxine therapy. These results suggest that long-term thyroxine treatment in patients with SCH, as well as OH is
associated
with decreased in LDL-C and Apo B levels, which might have a beneficial effect on the development of atherosclerotic coronary heart disease. (J Kor Sor Endocrinol 7:31~38, 1992)
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