The Effects of Exercise and Dietary Protein on Leucine Oxidation in Laboratory Rats

Oxidation of the essential branched-chain amino acid, leucine (leu), increases in response to exercise. The purpose of this thesis was to investigate the effects of exercise and dietary protein on leu metabolism by measuring in vivo leu oxidation (leu ox) and in vitro branched-chain alpha-keto acid dehydrogenase (BCKAD) activities in female rats. An assay for BCKAD activity in skeletal muscle, liver, and kidney was developed and used, in addition to leu ox measurements. The first study examined the effects of low (8%) and high (23%) protein diets, and exercise on leu ox and BCKAD activities in skeletal muscle, liver, and kidney. Untrained female rats were either exercised for 60 minutes or remained sedentary. The second study was designed to investigate the adaptive effects of exercise training (20 wks) on leu ox and BCKAD activities in skeletal muscle and liver at rest and immediately following a 60 minute exercise bout in female rats. The data demonstrated that (1) high dietary protein resulted in increased leu ox and increased hepatic basal and total BCKAD activities compared to low dietary protein; (2) dietary protein level did not affect muscle and kidney BCKAD activities; (3) a bout of exercise led to increased leu ox compared to sedentary animals and this effect was reduced with training; (4) exercise-associated increases in leu ox in untrained animals were accompanied by increases in basal BCKAD activity in liver and muscle; (5) low protein-exercised animals oxidized 2-fold more leu than low protein-sedentary animals, while the high protein-exercised group oxidized only 20% more leu than the high protein-sedentary group; and (6) training results in an increased capacity to oxidize leu in skeletal muscle and liver.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Food Science

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Hendrix, Melissa Kay

Contributors dc:contributor

• Layman, Donald K.

• Chemistry, Biochemistry
• Health Sciences, Nutrition

Language dc:language

eng

Identifier

(UMI)AAI8823143

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/77465