EFFECT OF 2-METHOXYESTRADIOL ON GONADOTROPIN SECRETION AND OXIDATIVE STATUS OF PORCINE PITUITARY CELLS IN VITRO

The aim of the study was to investigate the effect of 2-methoxyestradiol (2-ME) on GnRH-induced LH and FSH secretion by porcine pituitary cells in vitro. Moreover, the concentrations of superoxide anion radical (O-2(-)), as a possible mediator of 2-ME action, and malonyldialdehyde (MDA), as an oxidative stress indicator, were estimated. Pituitary cells were cultured in McCoy 5A medium with GnRH (positive control), with GnRH and 3.3x10(-11)-3.3x10(-7)M/L of 2-ME, or with GnRH and 2.7x 10(-9)-2.7x10(-s) M/L of 17 beta-estradiol. The secretion of gonadotropins, as well as concentrations of superoxide anion and MDA were analysed after 2-72 h of the experiment. A positive correlation between 2-ME dose and FSH secretion from anterior pituitary cells (r=0.72, 0.95, 0.92, 0.90, 0.85, and 0.82 after 2, 6, 18, 24, 48, and 72 h, respectively) was demonstrated. In contrast, a negative correlation between 2-ME concentration and LH secretion was observed (r=-0.82, -0.72, -0.85, -0.89, -0.93, and -0.79 after 2, 6, 18, 24, 48, and 72 h, respectively). The concentration of O-2(-) was increasing under the influence of the rising doses of 2-ME, whereas the mean level of MDA was not changing significantly.