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:
“When the whole world is writing letters, it’s easy to lap into the quiet within, tell the story of an hour, keep alive the narrating inner life. To be alone in the presence of one’s thought is not a value, only a common practice.”
—Vivian Gornick (b. 1935)
“However strongly they resist it, our kids have to learn that as adults we need the companionship and love of other adults. The more direct we are about our needs, the easier it may be for our children to accept those needs. Their jealousy may come from a fear that if we adults love each other we might not have any left for them. We have to let them know that it’s a different kind of love.”
—Ruth Davidson Bell. Ourselves and Our Children, by Boston Women’s Health Book Collective, ch. 3 (1978)