Non-human primate platelets and arterial tissue cannot convert preformed [14C]lanosterol into[14C]cholesterol in vivo.

In contrast with the prevailing view, we report the inability of non-human primate platelets or arterial tissue to complete the biosynthesis of [14C]cholesterol from [14C]mevalonic acid in vitro or in vivo, or from performed [14C]lanosterol in vivo. The latter observation suggests that these tissues lack one or more components of the methyl sterol demethylase system.