CHARACTERISTICS OF THYROID STATUS IN EXPERIMENTAL LIVER METASTASIS

Aim of the study was to analyze the dynamics of thyroid hormones in the pituitary gland, thyroid gland (TG) and blood serum (BS) in liver metastases to reveal thyroid profile of metastasis and to find thyroid markers-of metastasis in BS.

The experiment included 44 white male rats weighing 180-250 g. Sarcoma 45 (S-45) was transplanted intrasplenically after the spleen was brought under the skin. Levels of thyroid hormones: thyroid stimulating hormone (TSH) in the pituitary gland, TG, BS; free (FT4) and total (T4) thyroxine and free (FT3) and total (T3) triiodothyronine in TG and BS were studied by radioimmunoassay (Immunotech, Czech Republic; Arian analyzer, Russia).

From the first days of the tumor development, pituitary gland strain with TSH hyperproduction was observed, and later TG hypofunctioning developed. Quantitative changes of thyroid hormones in organs did not correspond to their dynamics in BS. First diagnostic signs of experimental liver metastases, under the absence of formed metastases in the organ, were hyper-TSH-emy and the tendency to FT3 decreasing in BS. Typical characteristics of the "climax" of liver metastasis included formation of a marked "low TB" syndrome which transformed into a more severe "lowT3/lowT4" syndrome in secondary metastasis to the lungs.

Thus, primary tumor growth and development of metastases are accompanied by the strain and imbalanced functioning of the thyroid system. Analysis of dynamics of the thyroid axis hormones in BS allows prognosis of liver metastases, as well as contributes to identifying the point of no return for the disease development which leads to secondary metastasis and irreversible progression of the process.