Relationship of hypoglycemia to tumor necrosis factor production and antitumor activity: role of glucose, insulin, and macrophages.

The role of hypoglycemia in tumor necrosis factor (TNF) production was examined. TNF was produced from sera of animals presensitized with reticuloendothelial system stimulants after lipopolysaccharide (LPS) challenge. Blood glucose was strongly reduced during TNF production. Glucose administration to presensitized mice (before LPS challenge) caused inhibition of TNF production. Exogenous insulin injection inhibited TNF production in a dose-related manner. Peritoneal exudate cells (PEC) from Propionibacterium acnes-primed mice revealed increased glucose consumption during in vitro TNF production but showed no relationship between the degree of glucose consumption and the ability to produce TNF. Insulin addition to the culture medium caused inhibition of TNF production from PEC, which indicated that insulin may block TNF production from macrophages. Administration of highly purified TNF (without concomitant LPS) induced extensive tumor necrosis but did not induce hypoglycemia; LPS induced moderate necrosis with accompanying hypoglycemia; insulin induced hypoglycemia but did not induce tumor necrosis. It is concluded that hypoglycemia does not accompany the action of TNF.