We report the cases of two individuals, one in Tacoma, WA, and the second in San Diego, CA, whose deaths were attributed to ingestion of 2,4-dinitrophenol (2,4-DNP). 2,4-DNP has historically been used as a herbicide and fungicide. By uncoupling mitochondrial oxidative phosphorylation, the drug causes a marked increase in fat metabolism that has led to its use to aid weight loss. Both cases reported here involved its use for this purpose. Features common to both cases included markedly elevated body temperature, rapid pulse and respiration, yellow coloring of the viscera at autopsy, history of use of weight loss or body building supplements, and presence of a yellow powder at the decedent's residence. Because of its acidic nature, the drug is not detected in the basic drug fraction of most analytical protocols, but it is recovered in the acid/neutral fraction of biological extracts and can be measured by high-performance liquid chromatography or gas chromatography-mass spectrometry. The concentration of 2,4-DNP in the admission blood samples of the two deaths reported here were 36.1 and 28 mg/L, respectively. Death in both cases was attributed to 2,4-DNP toxicity. Review of information available on the internet suggests that, although banned, 2,4-DNP is still illicitly promoted for weight loss.

Increased proportions of phosphatidylethanolamine (PE) are a common adaptation of poikilothermic animals to life at cold temperatures. Although amino‐phospholipids such as PE are asymmetrically distributed between the two membrane hemilayers, the impact of temperature‐induced changes in phospholipid composition on PE asymmetry has not been examined. Accordingly, the distribution of PE between the inner and outer hemilayers of the inner membrane of liver mitochondria was determined in rainbow trout (Oncorhynchus mykiss) acclimated to 20°C and 5°C. Mitochondria were isolated from trout liver by a combination of differential and Nycodenz™ density‐gradient centrifugation, resulting in an 11‐ to 15‐fold enrichment in the activity of the mitochondrial enzyme marker succinate cytochrome c reductase. Interestingly, the outer mitochondrial membrane was more stable in 5°C‐ than 20°C‐acclimated trout as indicated by the higher concentration of digitonin (0.6 vs. 0.3 mg digitonin/mg mitochondrial protein) required for the preparation of mitoplasts. Phosphatidylethanolamines in the outer hemilayer of the inner mitochondrial membrane (IMM) were identified as derivatives of 2,4,6‐trinitrobenzene sulfonic acid (TNBS), a nonpenetrating reagent that reacts with primary amines. Our results demonstrate 1) a decrease in the phosphatidylcholine:phosphatidylethanolamine ratio in the IMM of 5°C‐ (1.43 ± 0.09) compared to 20°C‐ (2.31 ± 0.34) acclimated trout and 2) smaller amounts of PE in the outer hemilayer (6.0 ± 0.51%) of the IMM from 5°C‐ than 20°C‐acclimated trout (8.1 ± 0.55%). These results indicate that the composition of the inner mitochondrial membrane is enriched in PE at cold temperatures and that this enrichment is largely restricted to, and therefore most likely to be of functional significance to, the inner hemilayer. © 1996 Wiley‐Liss, Inc.

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