Gluconeogenesis from alanine in patients with progressive malignant disease

We have studied by tracer technique the conversion of the carbon skeleton of alanine to glucose in patients with progressive malignant disease. These data have been compared to similar studies done in patients with chronic undernutrition from other causes. The results show increased conversion of alanine to glucose 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 carbon conversion is considerably less (alanine carbon, 5.6 mmol/hr, versus pyruvate carbon, 39 mmol/hr). Exogenous glucose resulted in good suppression of alanine-to-glucose conversion as it does in normal subjects. It did, however, result 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. We conclude that uncontrolled gluconeogenesis from alanine is probably not significant in terms of energy expenditure in the patient with uncontrolled cancer.