Background: Hormone replacement therapy (HRT) during menopause exerts an essential impact on neuroendocrine regulation within the hypothalamic-pituitary system. The sex steroids, especially estrogens, are responsible for the synthesis and secretion of neuropeptides and neurotransmitters, such as galanin, neuropeptide Y, the opioid peptides, dopamine, serotonin, and others. The purpose of our research was to evaluate the concentration of galanin in postmenopausal women before and after the application of HRT, and to compare these values to the concentrations found in women of reproductive age.
Material/Methods: The experimental group consisted of 20 women (average age 53I5.2). The average time elapsed since the last menstruation in these women was 5.3 year &plusm; 1.4.
Results: The differences in the concentrations of galanin before (8.24&plusm;3.62 pg/ml) and after (5.63&plusm;2.75) the application of HRT were not statistically significant. These values were significantly lower, however (p<0.05), than the galanin concentrations in women of reproductive age (22.03&plusm;12.02 pg/ml). The concentrations of estradiol prior to the administration of HRT (0.021&plusm;0.02 ng/ml) were significantly lower (p.<0.001) than after the application of hormone replacement therapy (0.09&plusm;0.156 ng/ml). The concentrations of estradiol in the control group averaged 0.070&plusm;0.04 ng/ml, significantly higher than in the group of post-menopausal women given HRT (p.<0.05). No statistically significant difference was found between the galanin concentration in women of reproductive age and in postmenopausal women using HRT.
Conclusions: Our research results indicate that serum galanin in postmenopausal women is significantly lower than in women of reproductive age. The application of hormone replacement therapy does not restore galanin concentrations to levels typical for women of reproductive age.

Keywords: galanin, Estrogens, Menopause, menopausal symptoms