[Na⁺ + K⁺]ATP-ase in Liver and Brain of Obese Mice

Summary

The activity of hepatic [Na⁺ + K⁺]ATP-ase showed a genedosage relationship in 6 week old mice. Before weaning hepatic [Na⁺ + K⁺]ATP-ase activity was normal in preobese mice but fell within 7 days of weaning to the low levels observed in older ob/ob mice. Brain [Na⁺ + K⁺]ATP-ase activity was unchanged in ob/ob mice although [³H]-ouabain binding was reduced. Arrhenius plots of [Na⁺ + K⁺]ATP-ase activity in liver and brain and of [³H]-ouabain binding to brain preparations showed breakpoints at lower temperatures in ob/ob than lean mice. These breakpoints were altered by pretreatment of tissue with deoxycholate. It is suggested that changes in membrane lipid composition might be an important factor regulating [Na⁺ + K⁺]ATP-ase in ob/ob mice

Key-Words:

Gene-Dosage - Age - Arrhenius Plots - Deoxycholate