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Biomedical subjects

G A Sacher

Publications and source records attributed to G A Sacher.

10 recordsLinked to original sources
PubMed1979

Genetic relation of life span to metabolic rate for inbred mouse strains and their hybrids.

Average life spans were estimated for the male progeny from 21 of the 25 possible matings of 5 inbred mouse strains. Oxygen consumption was measured in an open system over a 48-hour interval. Resting metabolism, Mre, and average metabolism, Mav, were determined at 6-8 months of age, and at 24-34 months. Body weight, W, was determined at the time metabolism was measured. Life span, L, is negatively correlated with Mre and Mav, and positively correlated with W at both ages of measurement. This is in accord with the metabolic wear factor that had previously been established among 85 different species of mammals. A new metabolism variable, the energy partition coefficient, defined as the ratio of average to resting metabolic rate, Mav/Mre, has a parabolic relation to body weight, i.e., is maximal at an intermediate body size. The squared body weight deviation in turn has a negative correlation with life span. The correlation of L with Mav/Mre is positive, as expected, but not significant. These data suggest the existence of a longevity factor dependent on the partition of energy between the phasic metabolism of activity and the continuous maintenance metabolism.

Aging↗
PubMed1976

Age-dependence of body weight and linear dimensions in adult Mus and Peromyscus.

Head plus body length (HBL), tail length (TL) and body weight (BW) were measured on two species of small myomorph rodents, Mus musculus and Peromyscus leucopus, throughout adult life. Both sexes of Mus show about a 15 per cent increase of HBL and TL between 5 and 24 months of age, and a BW increase of about 47 per cent. There is no age-trend of HBL in either sex of Peromyscus between 5 and 67 months of age, while TL increases about 7 per cent. In both species, cessation of skeletal growth is followed by a steady decrement of body mass, which averages about 0.23 per cent per month throughout adult life for the two sexes of Peromyscus, and over two per cent per month after cessation of skeletal growth in Mus. The weight loss in Mus in the last half of the lifespan is shown to be associated with age, rather than with the duration of subsequent survival. This evidence against the hypothesis that the late weight loss in Mus is due to terminal disease.

Age Factors↗