In a group of patients with developed primary hypothyroidism the authors investigated in a longitudinal eight-month trial the effect of hormonal substitution therapy with thyroxine (T4) on the serum concentration of lipids, apolipoprotein B and lipoprotein (a)--risk factors for the development of early coronary sclerosis. In some patients--"responders"--gradually euhormonosis, normolipaemia are induced and clinical symptoms of hypothyroidism receded. In the second group of patients with hypothyroidism, so-called "non-responders" (n = 5) after eight months substitution treatment with thyroxine the anticipated effect does not occur and the investigated serum parameters improve only partially. The thyroxine, TSH levels and those of lipid parameters and apolipoprotein B persist in the zone of pathological values. The lipoprotein (a) concentration in both groups of patients with hypothyroidism does not change during thyroxine substitution and varies near baseline values. From the submitted observations the authors of the present work do not assume that thyroxine plays a part in the catabolism of lipoprotein (a) via LDL receptors, the activity and number of which increases along with the effect of thyroxine.

Keywords: Adult; Aged; Apolipoproteins B /blood/; Coronary Artery Disease /blood/; Female; Humans; Hypothyroidism /blood/; Lipids /blood/; Lipoprotein(a) /blood/; Longitudinal Studies; Male; Middle Aged; Risk Factors; Thyroxine /therapeutic use/