Influence of cholestyramine feeding on mevalonate-activating enzymes.

Phosphorylation and decarboxylation of mevalonic acid have been measured in different tissues of chicks fed a cholestyramine diet from hatching until 18 days of age. Hepatic and intestinal phosphorylation and decarboxylation of mevalonate were slightly although significantly increased from 15 days of treatment. Direct measurements of 5-pyrophosphomevalonate decarboxylase activity using the specific substrate of this enzyme corroborated these data. Brain enzymatic activities remained unaltered with respect to controls. These results suggest that enzymes responsible for the conversion of mevalonate to isopentenyl pyrophosphate from neonatal chick liver and intestine alter their activities in a coordinate fashion and may play an important role in the regulation of cholesterogenesis in these tissues.