[Concentrations of the main lipoprotein density classes in disturbances of thyroid function in man (author's transl)].

The concentrations of the main lipoprotein density classes and the postheparin lipolytic activity (PHLA) were determined in the plasma of 12 hyperthyroid and eight hypothroid patients in comparison with 12 euthyroid, metabolically healthy individuals. Low-density lipoproteins (LDL) and high-density lipoproteins2 (HDL2) were decreased in hyperthyreosis (p less than 0.01) and increased in hypothyreosis (p less than 0.01). No significant differences could be detected with respect to the concentrations of very low-density lipoproteins (VLDL) as well as for HDL3, whereas intermediate-density lipoproteins (IDL) were higher in hypothyreotics than in controls (p less than 0.05). PHLA was increased in hyperthyreosis (p less than 0.01) and decreased in hypothyreosis (p less than 0.01). The chemical composition of LDL and HDL2 as well as the apolipoprotein composition of the protein moiety of HDL2 in hyperthyreosis and in hypothyreosis did not significantly differ from those in the control group. When data from all individuals studied were analyzed, no significant relationship could be detected between the concentrations of VLDL and HDL2, whereas HDL2 and PHLA correlated in a negative manner (p less than 0.05). It is suggested that HDL2, in addition to LDL, acts as carrier protein for the cholesterol increasingly yielded in hypothyreosis.