The effect of IgG, F(ab)2 and serum on the glucose metabolism in human leucocytes.

The glucose metabolism in human leucocytes was strongly stimulated by IgG, independent of whether phagocytosis occurred or not. The percentage increase was highest in the pentose phosphate pathway. Maximum stimulation of the glucose oxidation occurred with an IgG concentration of 1-4 g/l. The insignificant effect of F(ab)2 fragments indicated that the Fc piece is necessary for the stimulation by IgG. In nonphagocytosing leucocytes, serum stimulated the lactate production more and the CO2 production less than indicated by the IgG content of the serum. During phagocytosis or with high IgG concentrations, serum increased the glucose oxidation to a greater extent that did IgG alone. These results indicate that IgG is one of the components in serum most important for the stimulation of glucose oxidation in leucocytes. Serum factors counteracting the stimulation of glucose oxidation by IgG in nonphagocytosing leucocytes may have a regulating effect in vivo.

The effect of serum from obese and normal weight men on glucose metabolism in leucocytes.

The influence of pooled serum from either obese or normal weight males on glucose metabolism in human leucocytes has been studied. Leucocytes from normal weight males were incubated with 10-90% pooled serum and either [U-14C], or [1-14C]glucose. Compared to serum from the normal weight males, serum from the obese group had a more stimulating effect on the 14CO2 and [14C]lactate production from [U-14C]glucose and on the 14CO2 production from [1-14C]glucose. The two serum pools had the same stimulating effect on the Embden-Meyerhof pathway as indicated by the formation of [14C]lactate from [1-14C]glucose. Calculations revealed that the activity in the pentose phosphate pathway was stimulated more by serum from obese, than from normal weight males. It is a possibility that increased stimulation of the pentose phosphate pathway may contribute to the development of overweight.

The transketolase assay of thiamine in some diseases.

Erythrocyte transketolase activity (ETKA) and the effect of adding thiamine pyrophosphate have been measured in a group of 27 healthy individuals and in 37 patients diagnosed as having diabetes mellitus, anemia, polyneuritis, or malnourishment secondary to vascular disease of the brain. The observed values for the malnourished group did not differ significantly from those for the control group. The low ETKA values in diabetes mellitus seem to be due to a reduced apoenzyme level resulting from the disease itself rather than thiamine deficiency. Polyneuritis patients had low values of ETKA. In the anemic group as a whole the values showed a difference of only marginal significance from those found in the control group, but the patients with pernicious anemia all had a highly significant elevation of the ETKA values. Although the absolute thiamine pyrophosphate effect differ, there are no significant differences in percentage of thiamine pyrophosphate effect between the groups. It appears that differences in the patient groups studied here reflect variations in apoenzyme levels rather than thiamine status.

Influence of hydrocortisone on granulocyte function and glucose metabolism.

Examination has been made of the influence of hydrocortisone on the in vitro phagocytosis and intracellular killing of Staphylococcus aureus by human neutrophils and the production of lactate and CO2 during phagocytosis of latex particles. In high concentrations, 0.5-2 mg per ml, hydrocortisone caused a significant reduction in the phagocytosis and the production of lactate. Neither the bactericidal activity nor the production of 14CO2 from (U-14C) glucose in phagocytizing leukocytes was influenced by these hydrocortisone concentrations.

The glucose oxidation in isolated leukocytes from female patients suffering from overweight or anorexia nervosa.

Leukocytes from controls and patients with either overweight or anorexia nervosa were incubated with [U-14C]glucose in buffer with or without 50 percent serum. The production of [14C]O2 was measured both under phagocytosing and nonphagocytosing conditions. On the average leukocytes from the two groups of patients produced less [14C]O2 than leukocytes from the controls. Sera from controls stimulated the glucose oxidation in control leukocytes more than sera from patients with anorexia nervosa and less than sera from overweight patients. Neither the insulin nor the glucose content of the sera was of importance for the results. We assume that other serum factors may contribute to the reduced glucose oxidation in leukocytes from patients with anorexia nervosa, whereas this is not the case for patients with overweight.