Peripheral Tissue Metabolism in Cancer-bearing Man

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Abstract
Whole-body tracer studies have documented abnormal glucose and amino acid kinetics in cancer-bearing man. Whether these abnormalities are related to systemic or local tumor effects is questioned. Forearm metabolism was examined in six patients with localized squamous cell carcinoma of the distal esophagus and six healthy normal male volunteers. Substrate arterio-venous differences and blood flow across forearm tissues were determined and substrate flux calculated. The mean forearm blood flow (ml min-1 100 ml forearm-1) was not significantly different between cancer patients (3.67 ± 0.12) and normal subjects (2.80 ± 0.40). The uptake of glucose (μmol min-1 100 ml forearm-1) was significantly higher in cancer patients (1.99 ± 0.45) compared to control subjects without weight loss (0.47 ± 0.18). Lactic acid release (μmol min-1 100 ml forearm-1) was significantly higher in cancer patients (-1.15 ± 0.35) compared to control subjects (-0.26 ± 0.14). There was no significant difference in the flux of individual amino acids between the groups, although the mean total nitrogen released from forearms of cancer-bearing patients was greater than that from normal controls. The arterial serum insulin level was significantly lower and the arterial plasma glucagon level significantly higher in cancer patients compared to control subjects. These data cannot be explained by weight loss alone and suggest a peripheral defect in metabolism in this group of cancer-bearing patients.