It is well established that lactate secreted by fermenting cells can be oxidized or used as a gluconeogenic substrate by other cells and tissues. It is generally assumed, however, that within the fermenting cell itself, lactate is produced to replenish NAD+ and then is secreted. Here we explore the possibility that cytosolic lactate is metabolized by the mitochondria of fermenting mammalian cel...

The oxidative capacity of cat skeletal muscles (soleus, gracilis, and gracilis chronically stimulated for 28 days) was derived from the total mitochondrial content in the muscle, the surface area of mitochondrial inner membranes, and respiratory activities of isolated mitochondria. Mitochondrial content was estimated by standard morphometry. The surface area of mitochondrial inner membranes per...

Cigarette smoking is one of the main risk factors for premature human death associated to a variety of respiratory and vascular diseases, and cancer due to containing Hundreds of toxicants. Rat mitochondria were obtained by differential ultracentrifugation and incubated with different concentrations (1, 10 and 100%) of standardized cigarette smoke extract (CSE). Our results showed that cigarett...

Saponin permeabilization of tissue slices is increasingly popular for characterizing mitochondrial function largely because it is fast, easy, requires little tissue and leaves much of the cell intact. This technique is well described for mammalian muscle and brain, but not for liver. We sought to evaluate how saponin permeabilization reflects aspects of liverenergymetabolism typicallyassessed i...

Amino acid incorporation by isolated intact rat liver mitochondria was severely inhibited by chloramphenicol, carbomycin, or sparsomycin, partially inhibited by emetine, and unatIected by erytbromycin or lincomycin. By contrast, amino acid incorporation by inner membrane-matrix fractions prepared from rat liver mitochondria by digitonin was strongly inhibited by emetine, erythromycin, and linco...

Mitochondria isolated from normal mammary glands taken from lactating and nonlactating C3H mice were compared with those isolated from mammary adenocarcinomas. Functional mitochondria could be obtained from the normal mammary glands only when milk was not present in the tissue prior to homogenization and when bovine serum albumin was added to the isolation medium. Albumin also protected tumor m...