Open AccessInteraction of Mixed‐Function Oxidation with Biosynthetic Processes
Author(s) -
Thurman Ronald G.,
Scholz Roland
Publication year - 1973
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1973.tb03035.x
Subject(s) - lipogenesis , chemistry , phenobarbital , tritium , metabolism , biochemistry , limiting , medicine , endocrinology , biology , physics , mechanical engineering , nuclear physics , engineering
Lipogenesis from glucose was studied in perfused livers from normal and phenobarbital‐pretreated rats by measurement of the incorporation of tritium from tritiated water and 14 C from from [U‐ 14 C]glucose into the lipid fraction. In the presence of aminopyrine, a substrate for NADPH utilizing mixed‐function oxidations, rates of tritium incorporation decreased to 82 and 57% of control in livers from normal and phenobarbital‐pretreated animals, respectively. Aminophenylpyrazolone, a demethylated product of aminopyrine metabolism, had no effect implicating that inhibition of lipogenesis by aminopyrine is due to the process of mixed‐function oxidation. It is concluded that both mixed‐function oxidation and fatty‐acid synthesis compete for extramitochondrial NADPH. These data indicate that NADPH supply may, under the extreme conditions of enhanced mixed‐function oxidation, be the rate‐limiting step for lipogenesis in liver.