Structure-Activity Relationships Between Perfluorinated Chemicals and Mitochondrial Respiration Rates

Abstract

Perfluorinated chemicals are synthesized compounds that are structurally derived from hydrocarbons, but have carbon-hydrogen bonds replaced with carbon-fluorine bonds. They have been shown to inhibit respiration in rat liver mitochondria in vitro. The objective of this investigation was to explore whether structure-activity relationships exist for the effects of perfluorinated chemicals on mitochondrial respiration. Freshly isolated rat liver mitochondria were incubated with increasing concentrations of one of fifteen different perfluorinated chemicals, after which oxidative phosphorylation was recorded polarographically with an oxygen electrode. Each analysis was performed with five concentrations of the respective perfluorinated chemical, and repeated with mitochondria isolated from five individual animals. The respiration profiles of structurally related perfluorinated chemicals were then compared to each other. For some perfluorinated chemicals, increased carbon-chain length corresponded with an increased impact on mitochondrial respiration. However, it appeared that the effect of chain length was secondary to the ability of the perfluorinated chemical to efficiently carry protons across the mitochondrial membrane.