Presence in Adults
It was believed that after infants grow up, most of the mitochondria (which are responsible for the brown color) in brown adipose tissue disappear, and the tissue becomes similar in function and appearance to white fat. However, more recent research has shown that brown fat is related not to white fat, but to skeletal muscle.
Further, recent studies using Positron Emission Tomography scanning of adult humans have shown that it is still present in adults in the upper chest and neck. The remaining deposits become more visible (increasing tracer uptake, that is, more metabolically active) with cold exposure, and less visible if an adrenergic beta blocker is given before the scan. The recent study could lead to a new method of weight loss, since brown fat takes calories from normal fat and burns it. Scientists were able to stimulate brown fat growth in mice, but human trials have not yet begun.
In rare cases, brown fat continues to grow, rather than involuting; this leads to a tumour known as a hibernoma.
Read more about this topic: Brown Adipose Tissue
Famous quotes containing the words presence and/or adults:
“We must watch over our modesty in the presence of those who cannot understand its grounds.”
—Jean Rostand (1894–1977)
“We never really are the adults we pretend to be. We wear the mask and perhaps the clothes and posture of grown-ups, but inside our skin we are never as wise or as sure or as strong as we want to convince ourselves and others we are. We may fool all the rest of the people all of the time, but we never fool our parents. They can see behind the mask of adulthood. To her mommy and daddy, the empress never has on any clothes—and knows it.”
—Frank Pittman (20th century)