Cerebellar degeneration may be recognized as a remote effect of a growing tumor. We have analysed serum concentrations of tumor necrosis factor-? (TNF-?), macrophage chemoattractant protein-1 (MCP-1), thyroxine and insulin to elucidate the pathomechanism which may be of importance for the development of central degeneration in cachectic Morris hepatoma bearing rats. Serum TNF-? and MCP-1 levels were evaluated by means of the ELISA system, while thyroxine and insulin were estimated by radioimmunoassay. Microscopic examination using hematoxylin-eosin, Nissl and Kl?ver?Barrera staining revealed an atrophy in the cerebellum, homogenization changes of Purkinje cells and decreased cell density of the granular layer. In the Morris hepatoma bearing animals serum MCP-1 content was elevated while TNF-, thyroxine and insulin concentrations were decreased. This study has demonstrated that circulating TNF- and MCP-1, together with decreased levels of insulin and thyroxine accompany and may produce a milieu of factors involved in mechanisms of the development of cerebellar degeneration in cachectic hepatoma bearing rats.