Therapeutic effects of dehydroepiandrosterone (DHEA) and its metabolites in obese-hyperglycemic mutant mice

Dehydroepiandrosterone (DHEA) fed at 0.4%, and its metabolites, 3 alpha-hydroxyetiocholanolone (alpha-ET) and 3 beta-hydroxyetiocholanolone (beta-ET), fed at 0.1%, had marked anti-hyperglycemic and anti-obesity properties in mutant mice with single gene obesity mutations (diabetes, db; obese, ob; viable yellow, Avy). The therapeutic effects differed depending on the mutation as well as the inbred background on which the mutation was maintained. These steroids prevented onset of hyperglycemia and reduced the rate of weight gain in C57BL/6J-db/db and ob/ob mice, whereas in C57BL/KsJ-db/db mice, only hyperglycemia was prevented. The viable yellow (Avy) mutant, exhibiting a more slowly developing obesity condition, responded to all steroids with a marked decrease in rate of weight gain associated with decreased plasma insulin concentrations. Steroid treatment of most mouse mutants was associated with normal or increased food intake, a feature that suggests a decrease in metabolic efficiency. In order to assess any potential energy wastage by steroid stimulation of futile cycles we looked at the rates of lipogenesis, gluconeogenesis and oxygen consumption in steroid-treated normal and mutant mice. With the possible exception of the rate of gluconeogenesis that in obesity mutants was consistently reduced to normal by treatment, no metabolic changes were of sufficient magnitude to account for the marked decrease in metabolic efficiency. All treatments potentiated the action of insulin. This potentiation may change the hormonal balance such that minor changes in the rates of many metabolic pathways may interact to produce a large decrease in metabolic efficiency.