What is non-shivering thermogenesis and which tissue mediates it?

What is non-shivering thermogenesis and which tissue mediates it?

• A. Heat production via skeletal muscle shivering.
• B. Heat production via white adipose tissue.
• C. Heat production via liver metabolism.
• D. Heat production without rhythmic muscle activity, primarily via brown adipose tissue that uses UCP1 to uncouple oxidative phosphorylation and release heat.

Answer: (D)

Non-shivering thermogenesis is heat production without rhythmic muscle activity. The primary tissue mediating this is brown adipose tissue, which is packed with mitochondria and the protein UCP1. When cold, the sympathetic nervous system activates brown fat to oxidize fatty acids, and UCP1 uncouples oxidative phosphorylation from ATP production. This means the proton gradient is released as heat instead of driving ATP synthesis, warming the body without shivering. White adipose tissue stores energy and doesn’t generate heat in this way, though beige fat can sometimes acquire thermogenic properties. The liver contributes to metabolism overall, but the key mechanism for non-shivering heat generation is brown fat with UCP1 uncoupling oxidative phosphorylation.

Non-shivering thermogenesis is heat production without rhythmic muscle activity. The primary tissue mediating this is brown adipose tissue, which is packed with mitochondria and the protein UCP1. When cold, the sympathetic nervous system activates brown fat to oxidize fatty acids, and UCP1 uncouples oxidative phosphorylation from ATP production. This means the proton gradient is released as heat instead of driving ATP synthesis, warming the body without shivering. White adipose tissue stores energy and doesn’t generate heat in this way, though beige fat can sometimes acquire thermogenic properties. The liver contributes to metabolism overall, but the key mechanism for non-shivering heat generation is brown fat with UCP1 uncoupling oxidative phosphorylation.