Effects of acute exercise on the gluconeogenic capacity of periportal and perivenous hepatocytes

The present study was conducted to examine the effect of a single bout of e xercise (rodent treadmill, 60 min at 26 m/min, 0% grade) on the gluconeogen ic activity of periportal hepatocytes (PP-H) and perivenous hepatocytes (PV -H) in fasted (18 h) rats. Isolated PP-H and PV-H, obtained by selective de struction following liver perfusion with digitonin and collagenase, were in cubated with saturating concentrations of alanine (Ala; 20 mM) or a mixture of lactate and pyruvate (Lac+1Pyr; 20: 2 mM) to determine the glucose prod uction flux (J(glucose)) in the incubation medium. Results show that, in th e resting conditions, J(glucose) from all exogenous substrates was signific antly higher (P < 0.01) in PP-H than in PV-H. Exercise, compared with rest, resulted in a higher J(glucose) (P < 0.01) from Lac+Pyr substrate in the P V-H but not in the PP-H, resulting in the disappearance of the difference i n J(glucose) between PP-H and PV-H. Exercise, compared with rest, led to a higher J(glucose) (P < 0.01) from Ala substrate in both PP-H and PV-H. Howe ver, the exercise-induced increase in J(glucose) (gluconeogenic activity) f rom Ala substrate was higher in PV-H than in PP-H, resulting, as from Lac+P yr substrate, in the disappearance (P > 0.05) of the difference of J(glucos e) between PP-H and PV-H. It is concluded that exercise differentially stim ulates the gluconeogenic activity of PV-H to a larger extent than PP-H, ind icative of a heterogenous metabolic response of hepatocytes to exercise.