title: Cold acclimation induces zonal heterogeneity in gluconeogenic responses to glucagon in rat liver lobule.
abstract: The relationship between the enhanced responses of gluconeogenesis to norepinephrine (NE) and glucagon and its zonal distribution was studied in liver lobules of cold-exposed rats by examination of preparations enriched for periportal hepatocytes (PP-H) and for perivenous hepatocytes (PV-H) by the digitonin-collagenase perfusion technique. In the control group, gluconeogenesis from lactate (10 mM) plus pyruvate (1 mM) was higher in PP-H than in PV-H. NE (100 nM) and glucagon (100 nM) increased the rate of gluconeogenesis by 80 and 70%, respectively, in both PP-H and PV-H. Gluconeogenesis in PP-H was unchanged by cold exposure. The rate in PV-H increased to the rate in PP-H at 5 days after cold exposure, and then the rate returned to the control value at 20 days. The gluconeogenic response to the alpha-adrenergic action of NE in both PP-H and PV-H doubled after 5 days. The response to glucagon tripled in PP-H and was cut in half in PV-H after 20 days. Phorbol 12-myristate 13-acetate (PMA; 1 microM), A-23187 (100 nM), and dibutyryl adenosine 3',5'-cyclic monophosphate (DBcAMP; 1 mM) increased the rate of gluconeogenesis by 200, 100, and 80%, respectively, in both PP-H and PV-H from the control group. The responses to PMA and A-23187 were unchanged by exposure to cold. The response to DBcAMP was doubled in PP-H and was cut in half in PV-H after 20 days of cold exposure.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Veterinary Physiology, College of Agriculture, University of Osaka Prefecture, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Shiota
authors.forename: M
authors.initials: M
authors.lastname: Inagami
authors.forename: Y
authors.initials: Y
authors.lastname: Fujimoto
authors.forename: M
authors.initials: M
authors.lastname: Moriyama
authors.forename: K
authors.initials: K
authors.lastname: Kimura
authors.forename: T
authors.initials: T
authors.lastname: Sugano
mesh_terms: D000064:Acclimatization; D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D002478:Cells, Cultured; D003080:Cold Temperature; D006597:Fructose-Bisphosphatase / Q000378:metabolism; D005934:Glucagon / Q000494:pharmacology*; D005943:Gluconeogenesis / Q000187:drug effects / Q000502:physiology*; D005974:Glutamate-Ammonia Ligase / Q000378:metabolism; D007700:Kinetics; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology*; D010729:Phosphoenolpyruvate Carboxykinase (GTP) / Q000378:metabolism; D010732:Phosphofructokinase-1 / Q000378:metabolism; D011770:Pyruvate Kinase / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D011942:Receptors, Adrenergic, alpha / Q000502:physiology; D015398:Signal Transduction; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013997:Time Factors
chemical_list: D011942:Receptors, Adrenergic, alpha; D000001:Calcimycin; D003994:Bucladesine; D005934:Glucagon; D010732:Phosphofructokinase-1; D011770:Pyruvate Kinase; D006597:Fructose-Bisphosphatase; D010729:Phosphoenolpyruvate Carboxykinase (GTP); D005974:Glutamate-Ammonia Ligase; D013755:Tetradecanoylphorbol Acetate; D009638:Norepinephrine