SuJean Choi, Ph.D. Research Lab

SuJean Choi, Ph.D. Research Lab

Our lab examines how the brain alters hunger, food intake, and subsequently body weight. The results of our studies will provide a broader picture of how organisms regulate and maintain their energy balance and respond to the external environment. In addition, they will add to the basic foundation towards understanding health problems such as obesity, eating disorders, metabolic disorders, and depression and contribute to the development of more effective therapeutic strategies.

Currently, we have two main areas under investigation.

Mechanisms underlying appetite suppressants

Appetite suppressants are used clinically to help patients control body weight by reducing hunger and food intake. While these drugs do suppress food intake and promote weight loss, they lose efficacy when given chronically. The mechanisms by which these types of drugs lose efficacy with chronic administration is presently unknown. Studies have demonstrated anatomical and functional relationships between serotonin and hypothalamic neuropeptides that modify hunger and food intake. Interactions with hypothalamic neuropeptides could contribute to the reduction in feeding that follows appetite suppressant administration. Current studies in the lab are designed to delineate brain circuits that are activated by appetite suppressing drugs and whether genetic manipulation of these brain circuits can alter feeding behavior and body weight gain.

Hypothalamic regulation of energy homeostasis

Hypothalamic function is important for the regulation of energy balance and is clearly involved in numerous animal models of obesity. In addition to feeding behavior, the hypothalamus regulates body weight gain, fat deposition, adrenocortical activity, insulin secretion, sympathetic activity and circadian rhythms. Lesions to a number of different hypothalamic subgroups result in unique patterns of obesity. Anatomically, the hypothalamus is a highly interconnected subdivision that is extensively connected to every region of the brain. The results of these studies will demonstrate a useful model for mapping the inputs/outputs of important appetite and metabolic control centers in the hypothalamus, and increase our basic understanding of the central mechanisms controlling energy homeostasis.

Selected Publications

  • Fernstrom, J.D. & Choi, S (2007) The development of tolerance to drugs that suppress food intake. Pharmacology and Therapeutics. 117(1): 105-122.
  • Choi, S., Blake, V., Cole, S., Fernstrom, J.D. (2006) Effects of chronic fenfluramine administration on hypothalamic neuropeptide mRNA expression. Brain Research 1087:83-86.
  • Bhargava, A., Dallman, M.F., Pearce, D., Choi, S. (2004) Long double-stranded RNA-mediated RNA interference as a tool to achieve site specific silencing of hypothalamic neuorpeptides. Brain Research Protocols. 13:115-25.