GABA level and GAD activity in human and mouse normal and neoplastic mammary gland

Our studies have demonstrated that GABA (gamma-aminobutyric acid) is detect able both in mouse and in human normal mammary gland and in neoplastic alte rations. We have also shown that GABA content in tumor was significantly hi gher than in normal tissue. The statistically significant difference in GAD (glutamine acid decarboxylase) activity between tumor and normal mammary t issue was also detected. The positive correlation between GABA content and GAD activity in tumor cells was observed both in human and in mice material s. The observed increase in GABA level and GAD activity in tumor tissue cou ld reflect an eventual local antitumor immune response, however, a hypoxia of tumor cells could also be considered. The role of GABA, GAD and GABA-erg ic receptors in cancerogenesis and in cancer progression is still to be cla rified and requires further studies; however, it may indicate that the know n agonists of GABA-ergic system (e.g. baclofen) can potentially modulate th e tumor growth.