Gluconeogenesis in perfused livers from dexamethasone-treated chickens.
Gluconeogenesis was studied in hemoglobin-free perfused livers from chickens that had received daily injections of dexamethasone sulfate for 5 days. Dexamethasone increased to approximately 160% the level of plasma glucose and doubled the content of hepatic glycogen in fed chickens. In the isolated perfused livers from chickens starved for 48 h after the last dexamethasone injection, the rates of production of glucose from lactate decreased by approximately 30% and biphasic changes in glucose production from fructose proceeded in parallel with biphasic changes in the production of lactate and pyruvate. Quinolinate had no effect on gluconeogenesis in both groups. NH4Cl markedly inhibited the production of glucose from pyruvate-lactate mixtures in dexamethasone-treated chickens but stimulated in controls. Aminooxyacetate reversed the effects of NH4Cl in dexamethasone-treated chickens. The data presented provide evidence indicating that the reaction of mitochondrial alanine aminotransferase plays an important role in the regulation of the hepatic gluconeogenesis in dexamethasone-treated chickens.
Kobayashi
T
T
Department of Veterinary Physiology, College of Agriculture, University of Osaka Prefecture, Japan.
Iwai
H
H
Uchimoto
R
R
Ohta
M
M
Shiota
M
M
Sugano
T
T
D000410:Alanine Transaminase / Q000378:metabolism; D000818:Animals; D002645:Chickens / Q000378:metabolism*; D003864:Depression, Chemical; D003907:Dexamethasone / Q000494:pharmacology*; D005632:Fructose / Q000378:metabolism; D005943:Gluconeogenesis / Q000187:drug effects*; D007773:Lactates / Q000378:metabolism; D019344:Lactic Acid; D008099:Liver / Q000378:metabolism*; D008112:Liver Glycogen / Q000096:biosynthesis; D008297:Male; D008930:Mitochondria, Liver / Q000201:enzymology
D007773:Lactates; D008112:Liver Glycogen; D005632:Fructose; D019344:Lactic Acid; D003907:Dexamethasone; D000410:Alanine Transaminase