Effects of fasting and insulin on hepatic phosphofructokinase (PFK)

Fasting of susceptible mice for 24 hr led to a sharp decrease of apparent hepatic PFK activity which was increased to near fed levels by incubation of cytosolic fractions with GSH. Incubation of the cytosols with GSSG reduced the PFK to a lower level-(GSSG insensitive activity). The action of insulin was to increase total PFK with a marked increase of the GSSG insensitive activity.