The effect of the administration of ethanol to rats on the thermal sensitivity of transplantable tumours.

1. Long-term maintenance of rats on a diet containing ethanol did not cause compensatory changes in brain synaptic membrane lipid composition, nor was there any change in membrane lipid order as measured by steady-state fluorescence polarization of DPH. 2. The lipid composition of MC7 tumour plasma membranes was also determined in ethanol-fed and then sucrose pair-fed controls. Dietary ethanol caused no change in the composition of phospholipid classes. There was, however, a tendency for an increase in C18 fatty acids and an increase in monounsaturated at the expense of unsaturated and polyunsaturated fatty acids. There was no significant change in cholesterol content. 3. Tumour membranes from ethanol-fed rats were not different in lipid order from their pair-fed controls. Tumour membranes were, however, significantly less ordered than synaptic membranes. 4. A single heat treatment of 44 degrees C for 1 h increased the survival time of rats bearing both MC7 and D23 foot tumours. No difference in their survival was seen between ethanol-fed and sucrose pair-fed controls.