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Biomedical subjects

G L Dohm

Publications and source records attributed to G L Dohm.

At least 145 records · Page 8Linked to original sources
PubMed1977

Adaptations to endurance training at three intensities of exercise.

This study was undertaken to investigate the influence of exercise intensity (running speed) on a number of alterations that are known to occur with exercise training. Rats were trained on three treadmill running schedules: 20 m/min, 27 m/min, and 35 m/min for 1 h/day. After 6 wk, lean body mass and body fat content were decreased to the same extent in all three trained groups. Thus, exercise appears to lower body fat by some mechanism that is not related to the amount of energy expended during exercise. Heart and adrenal gland weight-to-lean body mass ratios were increased by training. Heart weight-to-lean body mass ratio increased with increasing intensity of exercise but the adrenal weight-to-lean body mass ratio was independent of exercise intensity. Training increased muscle succinate dehydrogenase activity to the same extent in all three trained groups which suggests that the adaptation in respiratory capacity is not altered greatly by the intensity of training.

Adaptation, Physiological↗
PubMed1976

Lipid content and fatty acid composition of heart and muscle of the BIO 82.62 cardiomyopathic hamster.

Microscopic and analytical studies of the lipids in the heart and muscle of the BIO 82.62 myopathic hamsters and age-matched normal animals at the average ages of 33, 67, and 108 days were performed. Microscopic examinations did not show increased lipid depositions in the hearts of the diseased animals as was found in the BIO 14.6 strain. No consistent differences in the lipid content of the cardiomyopathic hamsters (BIO 82.62) and age-matched controls were observed in the three age groups except in the cholesterol content of muscle. Cholesterol increased significantly (P less than 0.01) in the 67 and 108 day old animals. This increase elevated the cholesterol/phospholipid ratio. Analysis of the fatty acid composition of triglycerides showed that the cardiomyopathic hamsters store more saturated fatty acids in both heart and muscle than do their normal counterparts. The abundance of more saturated fatty acids may imply that either the desaturation mechanism is altered in the diseased animals or that unsaturated fatty acids are preferentially utilized in other processes.

Aging↗
PubMed1975

Response of lipogenesis and fatty acid synthetase to physical training and exhaustive exercise in rats.

The effect of physical training and exhaustive exercise on fatty acid synthesis in rat liver and adipose tissue has been investigated. Exercise training (treadmill running) significantly (p less than 0.05) decreased body wt, eipdidymal fat pad wt, adipocyte size, and hepatic fatty acid synthetase activity. Training did not significantly affect adipose tissue cell number, lipogenesis from glucose-U-14C, or fatty acid synthetase. Exercise to exhaustion immediately prior to sacrifice significantly (p less than 0.05) decreased lipogenesis from glucose-U-14C and fatty acid synthetase in adipose tissue from trained but not untrained rats. Liver fatty acid synthetase was not significantly influenced by exhaustive exercise. The results of this study indicate that rats may adapt to physical training by decreasing adipose tissue lipogenesis during exhaustive exercise. This adaptation in energy metabolism may facilitate physically trained animals in conserving blood glucose during exhaustive exercise, thereby prolonging endurance.

Adipose Tissue↗
PubMed1975

Fatty acid and ketone body metabolism in the rat: response to diet and exercise.

This study was designed to measure the response of key enzymes of ketone body metabolism in heart, skeletal muscle, and liver to diet and exercise, two conditions known to influence ketone body utilization. A 3 (diet: control, high fat, or high carbohydrate) X 2 (kill condition: rested or exhausted) X 2 (training: trained or untrained) factorial design was used to estimate main experimental effects as well as identify significant interactions of the variables. Physical training (treadmill running) was associated with a doubling of the activity of skeletal muscle 3-oxoacid CoA transferase, a key enzyme in extrahepatic ketone body utilization. The activity of the rate-limiting enzyme of liver ketone body production, hydroxymethylglutaryl CoA synthetase (HMG CoA synthetase), was not greatly influenced by training or exhuastive exercise indicating that the metabolic control of the ketosis of exercise may more likely be a function of the supply of fatty acids to the liver rather than the activity of HMG CoA synthetase. Feeding a high fat diet, on the other hand, significantly increased the activity of liver HMG CoA synthetase, indicating that the ketosis of fat feeding may be of a different nature than that of exercise. The results of this study indicate that physical training is associated with biochemical adaptations in ketone body metabolism as well as fatty acid oxidation, and that trained individuals are metabolically better endowed to benefit from the ketosis of exercise than untrained individuals.

Acetyl-CoA C-Acetyltransferase↗
PubMed1975

Lipogenesis and glyceride synthesis in the rat: response to diet and exercise.

The responses of hepatic and adipose tissue malic enzyme (ME), citrate cleavage enzyme (CCE), glucose-6-phosphate dehydrogenase (G6PD), and glyceride synthetase (GS) to exercise training and exhaustive exercies and the potential of a high fat or high carbohydrate diet to modify these responses were studied in male Carworth rats. Characteristic elevation and depression of ME, CCE, and G6PD were decreased in skeletal muscle, liver, and adipose tissues of high carbohydrate-fed rats. A significant two-way diet-training interaction was indicated for hepatic ME and G6PD. This interaction resulted from an apparent training modulation of ME and C6PD responses to the high fat and high carbohydrate diets. Adipose tissue G6PD was significantly decreased by training. Exhaustive exercise performed immediately prior to sacrifice did not significantly alter ME or CCE activities in either liver or adipose tissues, but decreased adipose tissue G6PD in untrained rats. Exhaustion was also associated with decreased GS activity in muscle and liver. Physical training was associated with a significant increase in GS in muscle and adipose tissues. In contrast to glyceride synthesis, no increase in adipose tissue lipogenic potential was noted in response to training, indicating that the physically trianed rat may have an enhanced ability to store but not synthesize fatty acids.

ATP Citrate (pro-S)-Lyase↗