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R H BROWN

Publications and source records attributed to R H BROWN.

At least 19 recordsLinked to original sources
PubMed1964

OSMOTIC AND METABOLIC ALTERATIONS OF MITOCHONDRIAL SIZE.

Sustained contraction (dehydration) of rat liver mitochondria can be readily produced by increasing the tonicity of the outside media, provided Ca(++) is removed by EDTA, fatty acids are removed by albumin, and a source of chemical energy (mitochondrial substrate or ATP) is present. This was demonstrated both gravimetrically and turbidimetrically. It was also demonstrated that the net movement of sucrose and H(2)O under altered conditions of tonicity in mitochondria was dependent on the state of the mitochondria; e.g., in the presence of EDTA, diffusion was blocked, both into and out of mitochondria, whereas, in the presence of EDTA and electron-transport substrates, movement of sucrose and water out of mitochondria was increased. In the presence of Ca(++), gramicidin, or fatty acids, diffusion of sucrose into and out of mitochondria is very rapid. Mitochondria obey osmotic law only after Ca(++) and fatty acids are removed from them.

Adenosine Triphosphate↗
PubMed1964

ROLE OF EDTA AND METALS IN MITOCHONDRIAL CONTRACTION.

STUDIES COMPARING THE STATE OF HYDRATION AND DEHYDRATION OF RAT LIVER MITOCHONDRIA TO THEIR CONTENT OF ATP, CA, AND FATTY ACID, ALONG WITH THE RATE OF ATP HYDROLYSIS, AS WELL AS MICROSCOPIC APPEARANCE OF MITOCHONDRIA, HAVE LED TO THE FOLLOWING GENERALIZATIONS: 1. The competition between cationic translocations and water translocation for the available chemical energy (ATP) determines under many circumstances the water content of mitochondria. 2. Swelling of mitochondria by electron transport substrates is an example of the activation of the cationic translocations at the expense of water translocation. 3. Electron micrographic studies are interpreted to indicate that EDTA alone can cause condensation and dehydration of the mitochondrial matrix. However, both EDTA and substrate are necessary to remove appreciable quantities of water from mitochondrial intramembranous spaces. 4. Since the data in the accompanying report indicated that EDTA, in the absence of energy, decreased the permeability of mitochondrial membranes, it appears likely that ballooning of intramembranous spaces, following addition of EDTA, represents trapping of water between two semipermeable membranes following dehydration of mitochondrial matrix.

Adenosine Triphosphatases↗