EFFECT OF EXPOSURE DURATION ON SELECTED ENZYME INDICES OF COLD ACCLIMATIZATION
Abstract
The relative liver mass and the liver activities of glucokinase, glucose-6-phosphatase, malic dehydrogenase, and the rate of pyruvate formation from 3-phosphoglycerate were measured in rats exposed to cold (4 C) for periods of 2 days, 4 weeks, and 5 months. The data indicated the metabolic, cold-acclimatization process, insofar as the liver was concerned, consisting of three consecutive, but overlapping, stages. The first was an increased capacity to form blood sugar. This was evident after 2 days in the cold and persisted throughout all exposures. The second stage was an elevated heat producing capacity per unit of liver weight. This was reflected in 4-week cold-exposed animals by an increased glucokinase, malic dehydrogenase, and pyruvate formation rate. The third stage appeared between 1 and 5 months after entrance into the cold. It consisted of a regression of certain of the elevated activities per unit weight of liver and their replacement, insofar as the animal as a whole was concerned, by an increase in relative llliver mass. (VER MASS. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1961
- Accession Number
- AD0276011
Entities
People
- David A. Vaughan
- John P. Hannon