High glucose uptake in growing rats adapted to a low-protein, high-carbohydrate diet determines low fasting glycemia even with high hepatic gluconeogenesis.
The our objective was to investigate the adaptations induced by a low-protein, high-carbohydrate (LPHC) diet in growing rats, which by comparison with the rats fed a control (C) diet at displayed lower fasting glycemia and similar fasting insulinemia, despite impairment in insulin signaling in adipose tissues. In the insulin tolerance test the LPHC rats showed higher rates of glucose disappearance (30%) and higher tolerance to overload of glucose than C rats. The glucose uptake by the soleus muscle, evaluated in vivo by administration of 2-deoxy-[(14)C]glucose, increased by 81%. The phosphoenolpyruvate carboxykinase content and the incorporation of [1-(14)C]pyruvate into glucose was also higher in the slices of liver from the LPHC rats than in those from C rats. The LPHC rats showed increases in l-lactate as well as in other gluconeogenic precursors in the blood. These rats also had a higher hepatic production of glucose, evaluated by in situ perfusion. The data obtained indicate that the main substrates for gluconeogenesis in the LPHC rats are l-lactate and glycerol. Thus, we concluded that the fasting glycemia in the LPHC animals was maintained mainly by increases in the hepatic gluconeogenesis from glycerol and l-lactate, compensating, at least in part, for the higher glucose uptake by the tissues.
a Department of Chemistry, Federal University of Mato Grosso, Cuiabá, Mato Grosso, Brazil.
Mayara P
MP
Pereira
Samyra L
SL
Buzelle
Emanuele
E
Batistela
Diego L
DL
Doneda
Suélem A de
SA
França
Maísa P dos
MP
Santos
Cláudia M B
CM
Andrade
Maria A R
MA
Garófalo
Isis do C
Ido C
Kettelhut
Luiz C C
LC
Navegantes
Valéria E
VE
Chaves
Gisele L
GL
Bertolini
Nair H
NH
Kawashita
D000273:Adipose Tissue / Q000378:metabolism; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism*; D018753:Diet, Protein-Restricted; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D005215:Fasting / Q000097:blood*; D005943:Gluconeogenesis; D005947:Glucose / Q000096:biosynthesis*; D005951:Glucose Tolerance Test; D005990:Glycerol / Q000097:blood; D007328:Insulin / Q000097:blood; D019344:Lactic Acid / Q000097:blood; D008099:Liver / Q000378:metabolism*; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism; D010729:Phosphoenolpyruvate Carboxykinase (GTP) / Q000378:metabolism; D051381:Rats
D001786:Blood Glucose; D004040:Dietary Carbohydrates; D007328:Insulin; D019344:Lactic Acid; D010729:Phosphoenolpyruvate Carboxykinase (GTP); D005947:Glucose; D005990:Glycerol
captation du glucose; fasting; gluconeogenesis; gluconéogenèse; glucose uptake; growing rats; insulin sensitivity; jeûne; liver; protein restriction; rats en croissance; restriction protéique; sensibilité à l’insuline