Rates of gluconeogenesis in perfused liver of alloxan-diabetic fed rats

The maximal capacity of the liver to produce glucose was examined using a t echnique, which permited to investigate gluconeogenesis in diabetic fed rat s. Diabetes was obtained with an iv injection of alloxan (40 mg/kg). Livers from diabetic fed rats were perfused in situ and gluconeogenesis from diff erent glucose precursors were measured one week after alloxan injection. He patic gluconeogenesis from L-alanine (5 mM) was absent. However, increased urea, pyruvate and L-lactate production was observed during L-alanine infus ion. Differently of L-alanine, alloxan-diabetic fed rats showed increased h epatic glucose production from pyruvate (5 mM), L-lactate (2 mM) and D-frut ose (5 mM). Additionally, increased L-lactate production from pyruvate and pyruvate production from L-lactate were observed. However, pyruvate product ion from L-lactate was lower in the diabetic group when compared with contr ol group. Moreover similar tendency were observed for L-alanine and D-fruto se. Taken together our results demonstrate influence of the cytosolic redox potential (NADH/NAD(+) ratio) in the metabolic fate L-alanine. Additionall y, in contrast to L-alanine, diabetic rats not only showed increased rate o f glucose production from L-glutamine (5 mM) but also higher values than co ntrol rats.