High glucose uptake in growing rats adapted to a low-protein, high-carbohydrate diet determines low fasting glycemia even with high hepatic gluconeogenesis

• Published in: Canadian journal of physiology and pharmacology Vol. 92; no. 6; pp. 460 - 466
• Main Authors: Pereira, Mayara P, Buzelle, Samyra L, Batistela, Emanuele, Doneda, Diego L, França, Suélem A de, Santos, Maísa P dos, Andrade, Cláudia M B, Garófalo, Maria A R, Kettelhut, Isis do C, Navegantes, Luiz C C, Chaves, Valéria E, Bertolini, Gisele L, Kawashita, Nair H
• Format: Journal Article
• Language: English
• Published: Canada NRC Research Press 01.06.2014; Canadian Science Publishing NRC Research Press
• Subjects: Adipose Tissue - metabolism; Animals; Blood Glucose - metabolism; captation du glucose; Carbohydrates; Comparative analysis; Diabetes; Diet, Protein-Restricted; Dietary Carbohydrates - administration & dosage; fasting; Fasting - blood; Gluconeogenesis; gluconéogenèse; Glucose; Glucose - biosynthesis; Glucose metabolism; Glucose Tolerance Test; glucose uptake; Glycemic index; Glycerol - blood; growing rats; Health aspects; High-carbohydrate diet; Insulin; Insulin - blood; insulin sensitivity; jeûne; Lactic Acid - blood; liver; Liver - metabolism; Male; Muscle, Skeletal - metabolism; Phosphoenolpyruvate Carboxykinase (GTP) - metabolism; protein restriction; Rats; rats en croissance; restriction protéique; Rodents; sensibilité à l’insuline; Tissues; Brazil; restriction protéique; growing rats; liver; fasting; gluconeogenesis; jeûne; protein restriction; captation du glucose; insulin sensitivity; gluconéogenèse; glucose uptake; rats en croissance; sensibilité à l’insuline
• ISSN: 0008-4212; 1205-7541
• DOI: 10.1139/cjpp-2013-0346

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.