Next, members of the Bartfai lab designed several whole animal studies to confirm these findings and examine the pathways in the body that might be affected.
Lighting up Beautifully
The scientists suspected that insulin in the brain might work to warm the body through a specific pathway involving signals that traveled from the brain's preoptic area, down the spinal cord, to neurons that direct brown adipose tissue to expend energy to produce heat.
Brown adipose tissue, also known as brown fat, is distinct from white fat in that it burns calories rather than storing them. While in years past, brown fat was thought to exist in humans only when they are infants, recent studies have shown that brown fat deposits are also found in healthy adults, especially around their collarbones and necks. Interestingly, older people have less brown fat than younger people, and obese individuals have less than lean individuals.
To see if brown fat was activated by insulin in the brain, the Bartfai group collaborated with members of Seimens Medical Solutions, who are experts in imaging techniques. Specifically, the scientists examined the effect of insulin injections in the preoptic area of rats on brown adipose tissue using Computerized tomography (CT) scans and positron emission tomography (PET) scans. Rodents possess brown adipose tissue in two large masses on their backs between the shoulder blades.
When the activity of the brown fat was captured visually, the data confirmed the scientists' projections.
"After insulin injection into the preoptic area, the brown adipose tissue lights up very beautifully," said Sanchez-Alavez.
Next, Sanchez-Alavez led studies examining the effects of insulin on metabolism, specifically by measuring the effect of insulin injecti
Scripps Research Institute