UF Discovery May Solve Mystery Of How Body Maintains Constant Temperature

September 10, 2003

GAINESVILLE, Fla. — Most modern homes have an automatic thermostat, and now a University of Florida researcher’s new study shows the mysterious mechanism that maintains body temperature may work in similar fashion: with the help of a heat-regulating “switch.”

Controlled by molecules in every cell that regulate the capacity to hold heat, this thermodynamic switch monitors all the systems of the body, turning on spontaneously when its overall temperature drops much below its usual 98.6 degrees Fahrenheit or off when it begins to experience a fever, says Dr. Paul W. Chun, a professor of biochemistry and molecular biology at UF’s College of Medicine. Chun believes the switch is universal in all living systems. He is scheduled to present his findings Wednesday at the 226th National American Chemical Society meeting in New York.

Without the switch, the intense operations needed to keep living things alive and functioning would be disrupted by disease, environmental factors and other sources, causing body temperatures to skyrocket and leading to a virtual meltdown. The switch also keeps the body from turning into a Popsicle in frigid conditions.

And, Chun says, “Researchers who fail to consider it in their analysis of energy differences in biological systems risk a conclusion that is inadequate, inaccurate — or both.”

Scientists have long recognized that most warm-blooded creatures – including people – maintain a constant body temperature, but few have sought to find out why. Intrigued by the question of how the basic laws of thermodynamics could be applied to the interacting biological systems he has studied for 27 years, Chun built on a 30-year-old theory of thermodynamics that has been largely ignored because there was no way to test it at the time.

Chun developed a method to analyze the available and highly precise data, which he applied to a variety of interacting biological systems – protein folding, protein self-assembly, and interactions among proteins, and those between proteins and nucleic acids and cell membranes. He found they all exhibit this thermodynamic switch at the molecular level.

“At a well-defined stable temperature — 98.6 degrees Fahrenheit in the human body — there will be a negative Gibbs free-energy change, and the maximum work can be accomplished for such essential life processes as transpiration, digestion, reproduction or locomotion,” Chun said. The negative Gibbs free-energy change is controlled by the body’s capacity to hold heat.

Beginning today, Chun will be available at the Fort Lee Hilton in New Jersey, 201-461-9000. His office telephone number is 352-392-3356.