Succinate-tetrazolium Reductase Research Articles

Succinate tetrazolium reductase activity in the developing rat thymus.

ABSTRACT Postnatal development of the rat thymus was studied. Succinate tetrazolium reductase activity, expressed as μg formazan per gram of fresh thymus tissue, remained unchanged from the 3rd to the 294th day after birth. The activity of the enzyme was also found to be unchanged histochemically during the postnatal life of the rat. The thymus attained its maximum weight, about 500 mg, at the age of 50 days. Thereafter it decreased steadily, amounting to some 175 mg in rats about 250 days of age.

Studies on succinate-tetrazolium reductase systems: III. Points of coupling of four different tetrazolium salts III. Points of coupling of four different tetrazolium salts

An investigation has been made of the points of coupling between four tetrazolium salts and the respiratory chain (succinate to O 2) in rat-liver tissue suspensions. Each tetrazolium salt has been studied with four levels of tissue and under various incubation conditions. The effects of various respiratory-chain inhibitors on these reactions have been studied in order to localise where the tetrazolium salts are reacting with the respiratory chain. The reaction of nitro-blue tetrazolium with the respiratory chain is virtually insensitive to the presence of antimycin A, or to the level of O 2 in the incubation mixture. This and other evidence suggests that nitro-blue tetrazolium reacts almost completely at one site on the respiratory chain, possibly ubiquinone. C, N-diphenyl- N′-4,5-dimethylthiazol-2-yltetrazolium bromide, however, appears to react at two sites of roughly equal importance, one of which is sensitive to antimycin A; this latter site is in the region of cytochrome c. Of the other two tetrazolium salts investigated here, triphenyltetrazolium chloride reacts with the terminal oxidase, and 2- p-nitrophenyl-3- p-iodophenyl-5-phenyltetrazolium chloride reacts in a manner similar to C, N-diphenyl- N′-4,5-dimethylthiazol-2-yltetrazolium bromide. These results, combined with the results for neotetrazolium chloride in the preceding communication, are discussed in terms of previous reports in the literature and the applicability of using tetrazolium reduction for histochemical purposes.

Coenzyme Q and succinatetetrazolium reductase activity of neonatal rat kidney.

SummaryHistochemical studies of the low succinate-tetrazolium reductase activity found in tubular elements of the neonatal rat kidney cortex have shown that the low reductase activity is due to a low activity of the primary dehydrogenase and a lack of availability of optimum amounts of coenzyme Q. In addition, a correlation has been found between the low reductase activity, morphologic immaturity of renal tubular elements, and a lack of mitochondrial staining of these elements.

Coenzyme Q10 and succinate-tetrazolium reductase activity of proliferative lesions of liver.

ConclusionQuantitative histochemical studies of sections of normal liver, regenerating liver and Novikoff hepatoma have shown that the succinate-INT and alpha-glycerophosphate-INT reductase systems of these tissues are not saturated with respect to quinone. Compared to normal liver, degree of unsaturation is considerably greater in regenerating liver and hepatoma and largely accounts for those low reductase activities which are observed in these 2 tissues. Response of sections of regenerating liver and hepatoma to COQ10 and menadione differs. COQ10 is very effective in hepatoma. In regenerating liver COQ10 is relatively ineffective whereas enhancement of reductase activity brought about by menadione is profound.