Role of hypothalamic-pituitarygonadal regulatory axis in growth of melanoma В16/F10 in С57/BL6 mice

Abstract

Aim: to study the role of the hypothalamic-pituitary-gonadal (HPG) regulatory axis and its dermal analogue in C57BL/6 mice of both sexes with the growth of B16/F10 grafted melanoma. The studies were carried out in mice of both sexes of the C57BL/6 line, which were transplanted with B16/F10 melanoma by subcutaneous injection of 0.5 ml of a suspension of tumor tissue. In intact animals and in the animals 14 days after the tumor inoculation, the levels of gonadal releasing hormone (GnRH), LH and FSH, and estradiol (E2), total testosterone (T) and free testosterone (Tfr), progesterone (P4), as well as ERα and ERβ estrogen receptors, progesterone receptor (RP4) and androgen receptor (RA) were determined. Results. In the males, compared with the females, after melanoma transplantation, the latent period and average life spans were shorter, while their tumor volumes were larger. A 2.1-fold decrease in GnRH in the hypothalamus in males led to a 2.7- fold increase in the level of LH in the pituitary gland, while in females a 1.4-fold (p<0.05) increase in GnRH promoted an increase in LH and FSH in the pituitary gland by 3.4-2.7 times. The blood serum did not adequately reflect changes in hormones in the central and peripheral links. In females, only in their tumor samples, an increased content of GnRH, LH, FSH and sex hormone receptors was revealed, while in males, the level of regulatory peptides and some receptors also increased in the skin. The change in the activity of the HPG axis in the logarithmic phase of the growth of B16/F10 grafted melanoma had its gender specifics and was characterized by a disorder in the direct and reverse feedback loops. Melanoma contained in an increased amount of all the regulatory peptides, hormones and receptors of the HPG axis, which allowed it to provide autonomous regulation of its own growth.