GLUCONEOGENESIS FROM ALANINE IN PATIENTS WITH PROGRESSIVE MALIGNANT DISEASE

Abstract

Tracer technique was used to study the conversion of the C skeleton of alanine to glucose in patients with progressive malignant disease. These data were compared to similar studies done in patients with chronic undernutrition from other causes. Increased conversion of alanine to glucose was seen in the overnight fasting state as compared to the control group. Whereas the percentage increases are comparable to those found with pyruvate-glucose cycling in such subjects, the total amount of C conversion is considerably less (alanine C, 5.6 mmol/h, vs. pyruvate C, 39 mmol/h). Exogenous glucose resulted in good suppression of alanine-to-glucose conversion as it does in normal subjects. It resulted in increased glucose-to-alanine conversion, increased alanine levels and increased flux of alanine from the circulation. Although these latter data may not have specificity for the patient with advanced cancer, a strong dependence for carbohydrate and protein metabolism is suggested. Uncontrolled gluconeogenesis from alanine is probably not significant in terms of energy expenditure in the patient with uncontrolled cancer.