Influence of metallothioneins on zinc and copper distribution in brain tumours.

Metallothioneins take part in the homeostasis of the ions of the metals which are necessary for the proper metabolism of the organism (zinc, copper), in biosynthesis regulation of the zinc-containing proteins and also in the detoxication of metals from the tissues. They also protect the tissue from the effects of free radicals, radiation, electrophilic pharmacological agents used in the cancer therapy and from mutagens. The experimental materials were brain astrocytomas, benign gliomas and malignant gliomas. The levels of the metallothionein were determined by cadmium-haemoglobin affinity assay using the cadmium isotope (109Cd). The values of zinc and copper were determined by means of atomic absorption spectrophotometry. In our studies, the level of metallothioneins in the group of malignant neoplasms was slightly higher than the level of these proteins in the group of benign neoplasms. The correlation coefficient of the studied parameters proved an interrelation between the levels of zinc and copper and the content of metallothioneins. In malignant neoplasms, the level of zinc showed a positive relationship with the metallothionein level, whereas the copper content showed an inverse relationship. There was a statistical difference, but no significant difference, in the levels of copper between malignant and benign groups.