Karen A. Lacourse

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PhD, Psychology, University of Michigan, 1998
University of New Hampshire
McNair Scholar, 1992
Major: Animal Science
Mentor: Dr. Gale B. Carey - Associate Professor of Animal & Nutritional Science
Research Topic: The Effect of Exercise on Lactate Production and Oxidative Metabolism in Female Yucatan Swine

The Effect of Exercise on Lactate Production and Oxidative Metabolism in Female Yucatan Swine
This study examined the effects of exercise on the ability of adipose tissue to convert glucose to lactate, triglycerides (TG) and C02. The production of lactate has previously been linked to obesity, but the effects of exercise on lactate production have not been studied.

This half of the experiment used 10 swine - 6 exercisers (EX) were run on tread mills five days a week for 3 months, and 4 acted as controls (CN). After 3 months fat biopsies were carried out, the cells were isolated and then incubated with and without insulin and/or radioactive glucose for 90'. Greater than 60% of glucose was converted to lactate, 30-35 to TG and <5% to CO2 in both EX and CN. However, the total glucose metabolized was greater in CN than EX. With insulin, glucose metabolism continued to increase in CN (7.5%) and decrease in EX (-3.9%). Citrate Synthase activity was found to be unexpectedly higher in CN, yet the cell size was 20% smaller than EX.

The results of this experiment have produced consistent trends which don't show statistical significance, but this may be due to small sample size. These trends indicate that cells from EX metabolize less total glucose and produce less lactate than cells from CN, the difference is further magnified with the presence of insulin. This shift would allow for the adipose tissue to obtain its energy from other sources, thus making more glucose available to exercising muscle.