Table 1. TNFα treatment of MCF7 cells induces ceramide generation in the mitochondrial fraction.

MCF7 cells were treated with 3 nM TNFα for 18 h. At the end of the treatment, the mitochondrial fraction was prepared by fractionation as described in the Experimental section, and lipids were then extracted, and ceramide levels were measured using the DGK assay as described in the Experimental section. Results are means±S.D. for four independent experiments.

	Ceramide (pmol/nmol of phosphate)
	Control cells	TNFα-treated cells
Total	4.74±0.5	10.44±0.6*
Mitochondria	5.12±0.4	11.62±0.8*

* Significant difference (P<0.05) compared with the control.