Effects of endurance training on the gluconeogenic capacity of periportal and perivenous hepatocytes.
This study was undertaken to assess the effect of 8 weeks of endurance training (treadmill, last 4 weeks: 60 min at 26 m/min, 8-10% grade) on the gluconeogenic capacity of periportal (PP-H) and perivenous (PV-H) hepatocytes of overnight fasted rats. Isolated PP-H and PV-H, obtained by selective destruction after liver perfusion with digitonin and collagenase, were incubated with saturating concentrations of a mixture of lactate and pyruvate (20:2 mM; Lac+Pyr) or alanine (20 mM; Ala) to determine the glucose production flux (J(glucose)) in the incubation medium. Endogenous J(glucose) as well as J(glucose) from substrates were significantly higher (P<.05) in PP-H than PV-H in the untrained state. Following training, a selective increase (P<.05) in J(glucose) from endogenous substrates and from Lac+Pyr was observed in PV-H only, resulting in the disappearance (P>.05) of the difference of J(glucose) between PP-H and PV-H. It is concluded that the increase in the gluconeogenic capacity of the liver following endurance training is first observed in PV-H.
Bélanger
Patrice
P
Département de Kinésiologie, Université de Montréal, C P 6128, Succ Centre-Ville, H3C 3J7, Montreal, PQ, Canada.
Désy
François
F
Gauthier
Marie-Soleil
MS
Couturier
Karine
K
Lavoie
Jean-Marc
JM
D000409:Alanine / Q000378:metabolism; D000818:Animals; D002469:Cell Separation; D005260:Female; D005943:Gluconeogenesis / Q000502:physiology*; D005974:Glutamate-Ammonia Ligase / Q000378:metabolism; D006503:Hepatic Veins / Q000502:physiology*; D022781:Hepatocytes / Q000378:metabolism*; D007700:Kinetics; D019344:Lactic Acid / Q000378:metabolism; D010805:Physical Conditioning, Animal / Q000502:physiology*; D010807:Physical Endurance / Q000502:physiology*; D011169:Portal Vein / Q000502:physiology*; D019289:Pyruvic Acid / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
D019344:Lactic Acid; D019289:Pyruvic Acid; D005974:Glutamate-Ammonia Ligase; D000409:Alanine