[Effect of human serum lipoproteins on various indices of thyroid function in rats]

It was shown that 7 to 10 days' injection of lipoproteins (LPs), isolated from the human blood serum according to Burstein and Scholnick method, induces significant inhibition of the rat thyroid iodine-absorbing function. Alpha-LPs exert more evident inhibiting effect than beta + pre- beta-LPs, and beta + pre- beta-LPs from the oncological patients' blood serum have more pronounced inhibiting effect comparatively to the same fraction of the donors; blood serum. 10-days' LP injection is accompanied by thyroxine inhibition and iodothyrozine/iodothyronine ratio rise in the thyroid tissue. In the experiments in vitro and in vivo several Lp fractions decreased thyrotropin-stimulating effect on AMP accumulation in the rat thyroid gland. Possible mechanisms of LP action on the thyroid function are discussed. The study of LP effect on the thyroid function in homologous system is necessary. It is suggested that hyperlipidemia (hyperlipoproteinemia) is one of the factors, contributing to the thyroid function decrease with age and in patients with malignant tumors.