Kombinirovannoe deǐstvie teplovogo shoka i gliukokortikoidnykh gormonov na kul'tiviruemye kletki mlekopitaiushchikh.

The combined effect of heat shock and glucocorticoid hormone (dexamethasone--DM) on plasmacytoma culture cells has been investigated. Fibroblasts and splenocytes were used as control cell types. Heat shock failed to induce the main hsp68 in plasmacytoma cells, however, the rate of synthesis of a constitutive protein (c-hsp70) increased significantly. In general, plasmacytoma cells exhibit hyperthermosensitivity as compared to control. DM treatment before heat shock did not protect plasmacytoma cells against heat damage. Moreover, if DM was present in culture medium for 3 days before heat shock, the synthesis of c-hsp70 was not increased. Heat-shock treatment leads to some decrease in the number of intact glucocorticoid hormone gc-receptors and binding sites in the nucleus. However, the preserved number of intact receptors after heat shock is quite enough for the realization of all glucocorticoid hormone effects. Interestingly, DM itself inhibits the proliferation of plasmacytoma cells. Furthermore, the combined action of heat shock and DM leads to more pronounced inhibition of plasmacytoma cells, depending on the DM doze and the time of heat shock treatment. The role of increased expression of c-myc gene, characteristic for plasmacytoma cells, in all the phenomena observed is discussed.