Date of Award
Open Access Thesis
Obesity is one of the leading most health risks around the world, being especially problematic in the United States. A combination of high-fat diets and genetic abnormalities are to blame for the ever-growing number of obese individuals.
Melanocortin 4 receptors are vital for regulating energy expenditure and feeding behaviors; mutations of the receptors have been found to be the leading monogenetic cause of obesity. Using MC4R +/- haploinsufficient rats being fed a range of dietary fat, we investigated the physiological and motivational differences using a locomotor task, an operant task with fixed and progressive ratios, as well as a distraction operant task. Percentage of lipid deposits in the liver of each rat was also analyzed using the Area Fraction Fractionator probe for stereological measurements. MC4R +/- haploinsufficiency resulted in a phenotypic resemblance for adult-onset obesity that is worsened by poor dietary fat consumption. Results from the operant tasks indicate that motivational deficits due to MC4R +/- haploinsufficiency can be seen prior to the onset of obesity. Post-obesity motivational deficits may be dependent on dietary fat consumption. Given the full results, the MC4R circuit ties closely with the motivational dopamine circuit providing a possible target in the prevention of adult-onset obesity before developme
Steiner, A.(2019). Motivational and Physiological Dysregulation Due to Development and Onset of Obesity via Melanocortin 4 Receptor +/- Haploinsufficiency. (Master's thesis). Retrieved from https://scholarcommons.sc.edu/etd/5560