When food is scarce, the body slows its metabolic rate to conserve energy. Are there any other systems or processes that prioritize which organs receive nutrients?
Answer
Glucose is prioritized for the brain and erythrocytes over the muscle and adipose tissue, for example, by hormonal control.
The hormones insulin and glucagon respond to strarvation, insulin secretion falling and that of glucagon increasing. The glucose transporter, GLUT4, in muscle and adipose tissue is dependent on insulin, so that in starvation less-essential uptake of glucose to these tissues declines. The glucose transporters of erythrocytes and brain (e.g. GLUT1) do not depend on insulin, so the supply of glucose to these tissues, which absolutely require it, is not cut off.
References
Hormones and Starvation: http://www.ncbi.nlm.nih.gov/books/NBK22414/
Insulin and the GLUT4 Glucose Transporter: https://en.wikipedia.org/wiki/GLUT4
GLUT1, insulin-independent Glucose Transporter: https://en.wikipedia.org/wiki/GLUT1
No comments:
Post a Comment