Subcellular immunolocalization of alphafetoprotein (AFP) in cell lines established from Morris hepatoma 7777 and 8994. Lack of effect of dexamethasone on the ultrastructural detection of AFP in the 8994 cells.

The subcellular localization of alphafetoprotein (AFP) has been studied in two cell lines (McA-RH 7777 and McA-RH 8994) derived from Morris hepatomas 7777 and 8994, using immunoperoxidase labelling techniques. After fixation of the cells in a low concentration of glutaraldehyde, a hot saponin treatment was used to increase the permeability of their membranes without destroying their morphology. The perinuclear spaces, the lamellae of the endoplasmic reticulum and the saccules of the Golgi apparatus contain electron-dense precipitates; 90% of the 7777 cells and 55% of the 8994 cells in exponential phase of growth are AFP-positive. Dexamethasone, a synthetic glucocorticoid, increases AFP production by the 8994 cells without raising the number of AFP-positive cells.