title: Effects of epidermal growth factor (urogastrone) on gluconeogenesis, glucose oxidation, and glycogen synthesis in isolated rat hepatocytes.
abstract: Using isolated rat hepatocytes, we studied the effect of epidermal growth factor (urogastrone) (EGF-URO) on the incorporation of [3-14C]pyruvate into glucose and glycogen, on the incorporation of [U-14C]glucose into glycogen, and on the oxidation of [U-14C]glucose to 14CO2. The effects of EGF-URO were compared with those of glucagon and insulin. EGF-URO, with an EC50 of 0.2 nM, enhanced by 34% (maximal stimulation) the conversion of [3-14C]pyruvate into glucose; no effect was observed on the oxidation of glucose to CO2 and on the incorporation of either pyruvate or glucose into glycogen. The effect of EGF-URO on pyruvate conversion to glucose was observed only when hepatocytes were preincubated with EGF-URO for 40 min prior to the addition of substrate. Glucagon (10 nM) increased the incorporation of [3-14C]pyruvate into glucose (44% above control); however, unlike EGF-URO, glucagon stimulated gluconeogenesis better without than with a preincubation period. Neither insulin nor EGF-URO (both 10 nM) affected the incorporation of [U-14C]glucose into glycogen during a 20-min incubation period. However, at longer time periods of incubation with the substrate (60 instead 20 min), insulin (but not EGF-URO) increased the incorporation of [14C]glucose into glycogen; EGF-URO counteracted this stimulatory effect of insulin. In contrast with previous data, our work indicates that EGF-URO can, under certain conditions, counteract the effects of insulin and, like glucagon, promote gluconeogenesis in isolated rat hepatocytes.
authors.affiliation: Departament de Bioquimica i Fisiologia, Facultat de Biologia, Universitat de Barcelona, Spain.
authors.forename: F
authors.initials: F
authors.lastname: Moreno
authors.forename: M
authors.initials: M
authors.lastname: Pastor-Anglada
authors.forename: M D
authors.initials: MD
authors.lastname: Hollenberg
authors.forename: M
authors.initials: M
authors.lastname: Soley
mesh_terms: D000818:Animals; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D005934:Glucagon / Q000494:pharmacology; D005943:Gluconeogenesis / Q000187:drug effects*; D005947:Glucose / Q000378:metabolism*; D066298:In Vitro Techniques; D007328:Insulin / Q000494:pharmacology; D008099:Liver / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008112:Liver Glycogen / Q000096:biosynthesis*; D008297:Male; D010084:Oxidation-Reduction; D011773:Pyruvates / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D007328:Insulin; D008112:Liver Glycogen; D011773:Pyruvates; D004815:Epidermal Growth Factor; D005934:Glucagon; D005947:Glucose