Thyroid hormones stimulate metabolism practically in all cells providing all vital body functions. Influence of melanoma growth on the thyroid gland is poorly studied. The purpose of the study was to determine hormonal changes in the thyroid gland in dynamics of transplantable В16/F10 melanoma growth in male and female mice.
The study included male and female С57ВL/6 mice (n = 80) bearing subcutaneously В16/F10 melanoma. Levels of TSH, total T3 and T4 and free FT3 and FT4 were determined by the radioisotope method in the thyroid gland tissue in weeks 1-4 of melanoma growth.
Activation of thyroid gland was observed 1 week after melanoma transplantation: T4 increased by 1.3 times and Т3 and FТ3 by 1.6 times in females, FТ3 and FТ4 by 2.1 and 1.7 times in males. 2.1 times decrease in pituitary TSH was noted in females only. Gender differences were found 2 weeks after: while T4 level in females was unchanged, free forms of the hormone and total T3 decreased by 1.7-4 times, and TSH level was still low. In males T4 decreased by 37 times, Т3 by 26.7 times and FТ3 and FТ4 by 1.8 and 1.3 times, respectively, while TSH increased by 1.5 times. T4 and T3 content in females was normal by the 3rd-4th weeks of the experiment, while FT4 and FT3 decreased by 4.5 times; TSH level remained 1.4 times lower than the norm. Males showed decrease in levels of both total (by 1.5 times) and free (by 3.3 times) forms with normal TSH content. Significance of the revealed characteristics of melanoma development was proved as correction of the status in females was possible using 1,3-diethylbenzimidazole triiodide. As a result, life span increased by 30%, complete tumor resorption and recovery with preservation of reproductive function were observed in several cases. Profound thyroid hypofunction could not be corrected in males.
Gender differences were revealed in thyroid gland functioning in dynamics of melanoma development which included profound thyroid hypofunction with the loss of control by the pituitary gland in males and normal production of total forms with a decrease of free forms of the hormone in females. These differences can be taken into account in personalized concomitant treatment.
Clinical trial identification
Legal entity responsible for the study
Rostov Research Institute of Oncology
Ministry of Health of the Russian Federation
All authors have declared no conflicts of interest.