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UCP-3’s Role In Enhancing Fat Oxidation |
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Written by Robbie Durand
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Thursday, 12 February 2009 |
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Page 2 of 5
UCP-1: Works Great In Rats…Not So Well In Humans
UCP-1 is found predominately in brown adipose tissue and is responsible for thermogenesis (production of heat). When UCPs are turned on, there is an increase in heat production, metabolism and resting oxygen consumption. Beta-adrenergic receptor stimulation, due to pharmacological agents, has both acute and chronic effects on brown adipose tissue. UCP-1 activity increases within seconds of stimulation, while chronic stimulation over hours and days results in increased amounts of UCP-1 protein and increased activation of brown adipose tissue.14 As exciting as the research was on rats, the research on stimulating UCP-1 seemed to flop in humans. Rodents have a greater capacity for thermogenesis than humans. They have more brown adipose tissue than humans; they also have more UCP-1 than humans, which makes a specific UCP-1 drug unlikely to be effective for humans.
UCP-3: The Muscle-Uncoupling Protein
UCP-3, which has a 60 percent similarity to UCP-1, is highly expressed in skeletal muscle and, to a lesser extent, in brown adipose tissue and heart.18 UCP-3 is the only expressed in skeletal muscle, which makes it of particular interest to increasing metabolism. It is important to recognize that the level of UCP-1 protein is 200- to 700-fold greater than UCP-3 protein levels in skeletal muscle or BAT.19 Although UCP-3 is expressed at much lower levels than UCP-1, increasing UCP-3 may enhance thermogenesis.
Gene Manipulations Of UCP-3
It has been demonstrated that certain people who have defective UCP-3 gene expression have decreased fat oxidation.13 Decreased fat oxidation has also been documented in UCP-3-deficient mice.36 In recent studies of skeletal muscle of mice that overexpress UCP-3, there was an increased capacity for fat oxidation.37 Mice overexpressing UCP-3 have lower bodyweights than normal mice.20 Additionally, mice that overexpress UCP-3 are not only leaner, they eat more than other mice and have less body fat. Additionally, when obese, otherwise healthy subjects were placed on a 900-Kcal diet for six months, people lost weight at very different rates. Researchers were curious why there were differences in the amount of weight lost. Diet-sensitive subjects, who lost weight at a greater rate than diet-resistant subjects, had 25 percent higher UCP-3 expression levels than diet-resistant subjects.23 So, now that you understand that increasing UCP-3 can enhance weight loss, let’s examine how to increase UCP-3.
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Research and Review 
