Priming Effect of a Morning Meal on Hepatic Glucose Disposition Later in the Day.
We used hepatic balance and tracer ([3H]glucose) techniques to examine the impact of "breakfast" on hepatic glucose metabolism later in the same day. From 0-240 min, 2 groups of conscious dogs (n= 9 dogs/group) received a duodenal infusion of glucose (GLC) or saline (SAL), then were fasted from 240-360 min. Three dogs from each group were euthanized and tissue collected at 360 min. From 360-600 min, the remaining dogs underwent a hyperinsulinemic (4× basal) hyperglycemic clamp (arterial blood glucose 146 ± 2 mg/dL) with portal GLC infusion. The total GLC infusion rate was 14% greater in dogs infused with GLC than in those receiving SAL (AUC360-600min2,979 ± 296 vs. 2,597 ± 277 mg/kg, respectively). The rates of hepatic glucose uptake (5.8 ± 0.8 vs. 3.2 ± 0.3 mg ⋅ kg-1⋅ min-1) and glycogen storage (4.7 ± 0.6 vs. 2.9 ± 0.3 mg ⋅ kg-1⋅ min-1) during the clamp were markedly greater in dogs receiving GLC compared with those receiving SAL. Hepatic glycogen content was ∼50% greater, glycogen synthase activity was ∼50% greater, glycogen phosphorylase activity was ∼50% lower, and the amount of phosphorylated glycogen synthase was 34% lower, indicating activation of the enzyme, in dogs receiving GLC compared with those receiving SAL. Thus, morning GLC primed the liver to extract and store more glucose in the presence of hyperinsulinemic hyperglycemia later in the same day, indicating that breakfast enhances the liver's role in glucose disposal in subsequent same-day meals.
Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN genie.moore@vanderbilt.edu.|Diabetes Research and Training Center, Vanderbilt University School of Medicine, Nashville, TN.
Mary Courtney
0000-0002-3436-3630
MC
Moore
Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN.
Marta S
MS
Smith
Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN.|Diabetes Research and Training Center, Vanderbilt University School of Medicine, Nashville, TN.
Ben
B
Farmer
Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN.
Guillaume
G
Kraft
Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN.|Diabetes Research and Training Center, Vanderbilt University School of Medicine, Nashville, TN.
Masakazu
M
Shiota
Diabetes Research and Training Center, Vanderbilt University School of Medicine, Nashville, TN.|Department of Surgery, Vanderbilt University School of Medicine, Nashville, TN.
Phillip E
PE
Williams
Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN.|Diabetes Research and Training Center, Vanderbilt University School of Medicine, Nashville, TN.
Alan D
AD
Cherrington
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism*; D015153:Blotting, Western; D062408:Breakfast; D004285:Dogs; D004386:Duodenum; D005215:Fasting / Q000378:metabolism; D005260:Female; D005941:Glucokinase / Q000187:drug effects / Q000378:metabolism; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology; D015309:Glucose Clamp Technique; D006003:Glycogen / Q000378:metabolism; D024981:Glycogen Phosphorylase / Q000187:drug effects / Q000235:genetics; D006006:Glycogen Synthase / Q000187:drug effects / Q000378:metabolism; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008112:Liver Glycogen / Q000378:metabolism*; D008297:Male; D010750:Phosphoproteins / Q000187:drug effects / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D013549:Sweetening Agents / Q000494:pharmacology
D001786:Blood Glucose; D008112:Liver Glycogen; D010750:Phosphoproteins; D013549:Sweetening Agents; D006003:Glycogen; D024981:Glycogen Phosphorylase; D006006:Glycogen Synthase; D005941:Glucokinase; D005947:Glucose