[Pentose phosphate pathway of carbohydrate metabolism in various systemic diseases of the connective tissue]

Ratios of activities of oxidative and nonoxidative enzymes involved in the pentose phosphate pathway of carbohydrate metabolism were altered in blood plasma and cells of the patients with systemic impairments of connective tissue. In rheumatoid arthritis and systemic lupus erythematosus the enzymatic activity was increased in blood plasma and cells, while the most distinct activation of the enzymes was found in granulocytes. In systemic sclerodermia total activity of the enzymes involved in metabolism of pentose phosphates in granulocytes exceeded 2.6-fold their values under conditions of normal state, whereas activities of the other enzymes studied remained near normal values. Calculation of ratios (mu value) between activities of the pathway oxidative and nonoxidative enzymes showed that the mu value was increased 2.7-fold in rheumatoid arthritis, while this value was decreased in lupus erythematosus and systemic sclerodermia 4.2- and 2-fold, respectively. The mu values, calculated on the basis of estimation of total activity of dehydrogenases from pentose phosphate pathway and total pentose phosphate metabolizing activity, might serve as a convenient diagnostic criterion for estimation of the ratio between activities of oxidative and nonoxidative enzymes involved in pentose phosphate pathway in granulocytes used for differential diagnosis of systemic impairments of connective tissue (rheumatoid arthritis, lupus erythematosus and systemic sclerodermia).