1. The increase in brain gamma-aminobutyrate, glutamate and aspartate and the decrease in brain glutamine that occur when ethanol is administered to rats in vivo could be reproduced by incubating brain homogenates from rats pretreated with ethanol. 2. For the demonstration of the effects of pretreatment with ethanol on the metabolism of gamma-aminobutyrate and glutamine, the whole homogenate could be replaced by various supernatant preparations, and even by the soluble protein fraction, which was less active, however. The ;postmitochondrial' sediment could likewise mediate the effects of pretreatment with ethanol. 3. When the brain homogenates from control and ethanol-treated rats were allowed to ;age' at 2 degrees for more than 7 days, the metabolic difference at incubation could no longer be demonstrated. The capacities of the homogenate from the control rats had changed to resemble those of ethanol-treated rats. 4. Data are given on the effects of the incubation time and of the concentration of homogenate.

Amino Acids↗

PubMed1967

Metabolic phases during the development of granulation tissue.

1. The metabolism of incubated slices of sponge-induced granulation tissue, harvested 4-90 days after the implantation, was studied with special reference to the capacity of collagen synthesis and to the energy metabolism. Data are also given on the nucleic acid contents during the observation period. Three metabolic phases were evident. 2. The viability of the slices for the synthesis of collagen was studied in various conditions. Freezing and homogenization destroyed the capacity of the tissue to incorporate proline into collagen. 3. Consumption of oxygen reached the maximum at 30-40 days. There was evidence that the pentose phosphate cycle was important, especially during the phases of the proliferation and the involution. The formation of lactic acid was maximal at about 20 days. 4. The capacity to incorporate proline into collagen hydroxyproline in vitro was limited to a relatively short period at 10-30 days. 5. The synthesis of collagen was dependent on the supply of oxygen and glucose, which latter could be replaced in the incubation medium by other monosaccharides but not by the metabolites of glucose or tricarboxylic acid-cycle intermediates.

Animals↗