Boston University Department of Biology

Faculty Profiles

Current Research

We are interested in the molecular and behavioral mechanisms that result in obesity or weight gain in mammals. To study this, we use several models of either adaptive or maladaptive weight gain. For example, pregnant mammals increase adiposity and weight as an adaptive response to the metabolic demands of pregnancy and subsequent lactation. Hibernating mammals also gain weight and adiposity as an adaptive response, in this case to the challenges of long-term fasting during hibernation. We are examining the endocrine, neural, and molecular mechanisms that promote such adaptive weight gain, in order to determine how mammals control their body mass and adiposity. Understanding the mechanisms of adaptive weight gain may provide clues to the causative factors of maladaptive weight gain (obesity). We are examining several models of maladaptive weight gain. In one, mice are fed diets composed of various combinations and amounts of fats (saturated or unsaturated) and carbohydrates.

We have found that mice fed high-fat diets gain weight without increasing energy consumption. The weight gain is associated with changes in hypothalamic expression of genes that mediate the actions of the satiety hormone leptin. We are also examining the effects of high fat diets on mice that are deficient in leptin (ob/ob mice), with or without leptin-replacement. It is hoped that using an approach that compares and contrasts the molecular mechanisms that result in adaptive vs. maladaptive fattening in mammals, it may be possible to better understand the etiology of obesity.

Courses Taught

• BI 315 Systems Physiology

Selected Publications

• Townsend KL, Lorenzi ML, and Widmaier EP. 2008. High-fat diet-induced changes in body mass and hypothalamic gene expression in wild-type and leptin-deficient mice. Endocrine 33:176-188.
• Townsend KL, Kunz TH and Widmaier EP. (2008). Changes in body mass, plasma leptin, and mRNA levels of leptin receptor isoforms during the premigration/prehibernation period in Myotis lucifugus. J Comp Physiol B, 178(2), 217-23.
• Schulz LC, Townsend K, Kunz TH and Widmaier EP. (2007). Inhibition of trophoblast invasiveness in vitro by immunoneutralization of leptin in the bat, Myotis lucifugus (Chiroptera). Gen Comp Endo 150, 59-65.
• Bruder ED, Lee JJ, Widmaier EP, and Raff H. (2007). Microarray and real-time PCR analysis of adrenal gland gene expression in the 7-day-old rat: effects of hypoxia from birth. Physiol Gen 29, 193-200.
• Reeder DM, Raff H, Kunz TH, and Widmaier EP. (2006). Characterization of pituitary-adrenocortical activity in the Malayan flying fox (Pteropus vampyrus). J Comp Physiol B, 176, 512-519.
• Reeder DM, Kosteczko NS, Kunz TH and Widmaier EP. (2006). The hormonal and behavioral response to group formation, seasonal changes and restraint stress in the highly social Malayan flying fox (Pteropus vampyrus) and the less social little golden-mantled flying fox (P. pumilus) (Chiroptera: Pteropodidae). Horm Behav 49, 484-500.
• Lee JJ and Widmaier EP (2005). Gene array analysis of the effects of chronic adrenocorticotropic hormone in vivo on immature rat adrenal glands. J Ster Biochem Mol Biol, 96, 31-44.
• Schulz LC and Widmaier EP. (2004). The effect of leptin on mouse trophoblast cell invasion. Biol Reprod, 71(6), 1963-7.

Text Books:

• Widmaier EP, Raff H, and Strang K. (2008). Vander’s Human Physiology: The Mechanisms of Body Function, 9th through 11th editions, McGraw-Hill Higher Education.
• Brooker R, Widmaier EP, Graham LK, and Stiling P. Biology. (2007). 1st edition. McGraw-Hill Higher Education

Trade Books:

• Widmaier EP: Why Geese Don’t Get Obese (and we do): How Evolution’s Strategies for Survival Affect Our Everyday Lives.  Publisher: W H Freeman and Co, NY (1998).
• Widmaier EP: The Stuff of Life: Profiles of the Molecules That Make Us Tick. Publisher: Henry Holt and Co, NY (2002).