Possible sites of interaction of acute renal failure with amino acid utilization for gluconeogenesis in isolated perfused rat liver

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Abstract
Experiments were performed to elucidate the mechanisms involved in the enhanced conversion of amino acids to glucose in acute uraemic rats. Increased gluconeogenesis from a mixture of serine, threonine, lysine, glutamate, ornithine and citrulline was confirmed using a non-recirculating perfusion system. Stimulation was concentration dependent, being most pronounced at physiological amino acid concentrations. Stimulation of glucose and urea formation could be mimicked by using serine alone whereas with lactate and pyruvate inhibition of gluconeogenesis was observed. Serine dehydratase activity was significantly elevated following nephrectomy. Further, the uptake of the non-metabolize amino acid alpha-aminoisobutyrate was considerably increased. It is concluded that serine may play a special role as substrate for the additional glucose formation in acute uraemic rats, probably mediated by an activation of serine dehydratase. Acceleration of amino acid transport seems to represent an additional component of stimulation of amino acid utilization in acute uraemia.