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Biomedical subjects

R L Huston

Publications and source records attributed to R L Huston.

33 records · Page 2Linked to original sources
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

Adipose tissue cellularity and lipolysis. Response to exercise and cortisol treatment.

Male rats a 5 wk of age were subjected to 13 wk of intensive treadmill running to study the effect of exercise on adipose tissue cellularity and lipolysis. Untrained controls of the same age remained sedentary in their cages for the duration of the experiment. Adipocyte numbers were similar in eqidiymal fat pads from trained and untrained rats (12.7 plus or minus 1.3 X 10(6) vs. 15.3 plus or minus 1.3 X 10(6) cells/pad), however trained rats had smaller fat pads containing smaller cells (0.09 plus of minus 0.01 vs. 0.20 plus or minus 0.04 mug triglyceride/cell). Adipocytes from trained rats possessed greater epinephrine-sensitive lipase activity than sedentary rats on a per cell, per milligram protein, per gram adipose tissue, or per fat pad basis. Although the smaller cells of the trained rats had greater epinephrine-sensitive lipase activity than the larger cells of the untrained rats, lipolysis was positively correlated with cell size within both treatment groups. Cortisol treatment of intact animals did not significantly affect in vitro adipose tissue lipolysis. The results of this study indicate that exercise training increased the potential of adipose tissue cells to release free fatty acids in response to epinephrine stimulation. Exercise training initiated at 5 wk of age had only a small effect on adipose tissue cell numbers but significantly decreased cell size.

Adenylyl Cyclases↗