I am interested in how animals perform all the incredible tasks that they do. I'm particularly fascinated with physiological processes operating at their limits- animals that "push the envelope". My current research explores the limits of fasting physiology; specifically investigating carbohydrate metabolism in fasting elephant seals. During periods of food shortage many animals enter a hypometabolic state (torpor, hibernation, etc.) and arouse during times of greater food availability. Northern elephant seals (Mirounga angustirostris), on the other hand, undergo neonatal development, molt, breed, lactate, and compete for mates while fasting (for up to 100 days in adult males). This makes elephant seals an ideal animal in which to explore the physiological adaptations to fasting. Much of this work involves extensive laboratory analysis. We've successfully implemented what were previously "laboratory only" techniques in the field; using radio-isotopic tracers we've measured gluconeogenesis, glucose cycle activity, and glycerol turnover in the fasting state. A number of our findings have been surprising and have forced us to reconsider what metabolic pathways may be important during fasting. Now I'd like to determine which metabolic substrates are contributing to the gluconeogenesis rates we've previously measured and quantify the contribution of glucose to overall metabolism. This will help elucidate the metabolic pathways used by fasting adapted animals to endure extended periods of fasting while meeting metabolic demands.

Fowler, M, Champagne, CD, Houser, DS, Crocker, DE (2008) Hormonal Regulation of Glucose Clearance in Lactating Northern Elephant Seals (Mirounga angustirostris). Journal of Experimental Biology 211, 2943-2949

Houser, DS, Champagne CD, Crocker DE. 2007. Lipolysis and glycerol gluconeogenesis in simultaneously fasting and lactating northern elephant seals. American Journal of Physiology- Regulatory, Integrative, and Comparative Physiology. 293, R2376-2381.

Champagne CD, Houser DS, Crocker DE. 2006. Glucose metabolism during lactation in a fasting animal, the northern elephant seal. American Journal of Physiology-Regulatory, Integrative, and Comparative Physiology.

Champagne CD, Houser DS, Crocker DE. 2005. Glucose production and substrate cycle activity in a fasting adapted animal, the northern elephant seal. Journal of Experimental Biology. 208(5):859-868.