1. Exposure of rats to 1% (w/w) of 2,2,4,4,6,8,8-heptamethylnonane in the diet for 2 weeks resulted in marked induction of liver peroxisome proliferation as judged from electron micrography, elevated activities of hepatic catalase (36%), cyanide-insensitive palmitoyl-CoA oxidase (10-fold), carnitine acetyl transferase (9.6-fold), lauric acid hydroxylase (12.4-fold), and the induction of the 80 K protein in SDS-polyacrylamide gel electrophoresis (4.1-fold).

2. 2,2,4,4,6,8,8-Heptamethylnonane dicarboxylic acid, a non-β-oxidizable fatty acid. was detected as the major metabolite in the liver, an example of an unmetabolizable lipophilic anion as a peroxisome proliferator.