Effect made by the growth of multiple primary malignant tumors on the hypothalamicpituitary-gonadal axis in BALB/c Nude mice of both sexes

Abstract

The aim was to study changes in the functioning of the hypothalamic-pituitary-gonadal (HPG) axis in BALB/c Nude mice of both sexes with multiple primary malignant tumors (MPMTs). The BALB/c Nude mice (n=84) of both sexes were divided into groups as follows: intact males and females (n=14), a reference group of mice of both sexes with standard subcutaneous inoculation of B16/F10 melanoma (n=14); the main group of mice with the reproduction of the MPMT model (n=14); B16/ F10 melanoma and Lewis carcinoma were inoculated into mice sequentially subcutaneously on two sides: one on the left side and the other on the right side. After 15 days of the growth of the malignant tumors, GnRH, LH and FSH contents were determined by ELISA using standard kits in 1% of the homogenates of the hypothalamic and pituitary tissues, and estradiol content (E2) was determined in 10% homogenates of ovaries and testes, as well concentrations of testosterone (T) and progesterone (P4) were identified in blood serum with the standard RIA kits (Immunotech, Czech Republic). Results. In the hypothalamus in females of the reference and main groups, the level of GnRH increased by 2.5-4 times, and in males it decreased by an average of 3.1 times; in response to those changes in animals of both sexes in the reference group and in the main group only in females in the pituitary gland the level of LH increased by 1.3-1.6 times, however a decrease in FSH in all groups was more pronounced in females: by 7.8-13.7 times and less pronounced in males: by 1.4-1.7 times (р˂0, 05). In the gonads of females, the level of E2 increased, but the levels of T and P4 decreased, while P4 increased in males. Blood parameters did not reflect hormonal changes in the organs. Conclusion. Abnormalities in the HHG axis performance, along with primary immunodeficiency, play a decisive role in overcoming antitumor protection for uncharacteristic malignant tumors.