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J Keilson

Publications and source records attributed to J Keilson.

5 recordsLinked to original sources
PubMed1979

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.

Adult↗
PubMed1978

The contribution of glucose to alanine metabolism in man.

We have studied by tracer technique the interconversion of the carbon skeleton of alanine with that of glucose. The data analysis is in terms of renewal theory rather than traditional compartmental analysis. This eliminates the need for estimation of compartment size, which is particularly difficult to determine in the case of alanine. In addition, the conversion rates between the two substances are found by considering the two components which are responsible for the determined radioactivity curves, namely, the first conversion of the labeled carbon and its subsequent movement in the product compound. The subjects of the study were for the most part underweight but had been hospitalized and eating a standard hospital diet for at least 3 days prior to the studies. Our data indicate that nearly twice as much carbon from glucose is cycled to alanine as is recycled from alanine back to glucose after a 14 hr overnight fast. Small amounts of glucose suppress the alanine-glucose arm of the cycle but probably do not change the glucose-alanine conversion. The contribution of glucose carbon to alanine metabolism is significant and appears to be immediately influenced by the magnitude of glycolysis.

Adult↗
PubMed1969

Cori cycle activity in man.

12 subjects have been studied after an overnight fast with trace amounts of pyruvate-3-(14)C and glucose-6-(14)C. Blood disappearance curves and incorporation of the pyruvate-3-(14)C label into blood glucose have been determined. By the use of transfer functions which allow processes with many different chemical steps to be examined as a unit, we have determined the per cent of pyruvate and presumably lactate which is regenerated into glucose. 8 of the 12 subjects showed that 7-23 mg/kg per hr are recycled, while 4 subjects fell well outside this range. Correlation of increased activity was not good with any demonstrated metabolic abnormality (diabetes or obesity), and it is suggested from clinical observation of the subjects that anxiety may play a role.

Adult↗