Changes in the content of hormones of hypothalamic-pituitary-thyroid axis in growth of single and multiple primary tumors in the presence of comorbidity

Introduction. Thyroid dysfunction is known to be associated with higher risks of cancer development. The purpose of this study was to analyze levels of thyroid axis hormones in the hypothalamus, pituitary gland, thyroid, and blood serum of male and female Balb/c Nude mice with B16/F10 melanoma and/or Lewis lung carcinoma. Material and Methods. Male and female Balb/c Nude mice were divided into groups: 1 - intact mice (n=7), 2 - mice with B16/F10 melanoma (n=7), 3 - mice with Lewis lung carcinoma (LLC) (n=7), 4 -mice with melanoma and LLC (n=7). Levels of thyroid-stimulating hormone (TSH), triiodothyronine (fT3), and thyroxine (fT4) were measured by RIA in homogenates of the hypothalamus, pituitary gland, thyroid and blood serum of all animals, and TH-releasing was measured by ELISA. Statistical processing of results was performed using the Statistica 10.0 program. Results. TH-releasing was reduced in the hypothalamus of all tumor-bearing mice, compared to initial values. TSH levels in the pituitary gland and thyroid were changed only in males with the combination of tumors (increased by 2.8 and 1.5 times, respectively). Levels of free forms of hormones in the thyroid in animals of both genders sharply increased, together with the elevation of TSH in the blood serum and, as a result, the decrease of 1Т3 and 1Т4 levels. Conclusion. Female and male Balb/c Nude mice of the studied groups demonstrated hypothalamic dysfunction manifested by the absence of regulation in the hypothalamus-pituitary-thyroid relationship, and by the hypothyroid status of animals.