Mitochondrial Population in Mammalian Cells

Abstract

The mitochondrial population, computed from the separate determination of the number of cells and mitochondria per gram of fresh rat liver, seems to decrease during carcinogenesis due to 4-dimethylaminoazobenzene, 4′-fluoro-4-dimethylaminoazobenzene, and 2-acetylaminofluorene. The noncancerigenic azodye, 2-methyl-4-dimethylaminoazobenzene, seems to provoke the formation of mitochondria within the liver cell. When 4-dimethylaminoazobenzene is incorporated in a complete diet, the mitochondrial population of the liver cell is unaffected. These results indicate that a lower mitochondrial population might be characteristic of a preneoplastic stage of rat liver induced by cancerigenic substances.

Studies on the Content and Organization of the Respiratory Enzymes of Mitochondria

“…The relative contribution of cytochromes c and c~ (13) to such spectra has been discussed in a previous communication (14) where it was shown that the absorption band at 551 m# is a composite, two-thirds of which is contributed by cytochrome c and one-third by cytochrome c~. The concentration of the various pigments reduced in the presence of substrate upon attaining an anaerobic condition is presented in Table I (4,5) on the studies of mitochondrial population of rat liver cells are summarized in Table II1. In order to relate these results to those presented above one must assume that the total nitrogen content (TNC) employed by Allard et al may be converted to the biuret protein determinations employed here, by the factor of 6.25.…”

Intracellular Distribution of 5' Nucleotidase in Rat Liver

“…The mitochondrial fraction (M) and supernatant fluid (S) each showed about 10 per cent of the homogenate (H) activity. It has been found previously, that on the average, 11 per cent of the total number of mitochondria was present in the isolated nuclear fraction (10). The very low level of enzymatic activity actually observed in the mitochondrial fraction indicated that the contaminating mitochondria in the nuclear fraction did not significantly influence the 5' nucleotidase activity of this fraction.…”

Studies on the particulate components of rat mammary gland. 3. The relationship between enzyme activity and particle counts in mammary gland suspensions

“…Counting, as a means of quantitative assay, has only recently been developed for use with mitochondrial suspensions (Allard, Mathieu, Lamirande & Cantero, 1952;Shelton, Schneider & Striebich, 1953;Agrell, 1955). In the present experiments particulate counts on suspensions of mammary tissue and on largeparticle suspensions obtained by the differential centrifuging of these suspensions have been carried out by the following modification of the procedure described by Allard et al (1952), with dark-ground illumination. The tissue or mitochondrial suspension was diluted by the addition of a calculated volume of ice-cold saturated (1-8M) sucrose.…”