Switching on the furnace: Regulation of heat production in brown adipose tissue.
Level 5 - mechanism / opinion, no new human data
Narrative review of molecular and physiological mechanisms without primary human trial data or systematic synthesis
PubMed 31325458 · doi:10.1016/j.mam.2019.07.005
What was done
This paper is a narrative review detailing the physiological and molecular mechanisms that activate uncoupling protein 1 (UCP1) and regulate non-shivering thermogenesis in mammalian brown adipose tissue (BAT).
What was found
The abstract reports no quantitative values or statistical effect sizes. It details multiple regulatory pathways of BAT thermogenesis: norepinephrine activates UCP1 using intracellular or extracellular free fatty acids; thyroid hormones act via type 2 deiodinase (DIO2 knockout causes cold intolerance in mice); parathyroid hormone, cardiac natriuretic peptides, gut hormones (secretin), and gut microbiota metabolites (butyrate) promote BAT activity. Additionally, the review notes non-UCP1 futile thermogenic pathways revealed by UCP1 knockout models, including creatine-dependent cycling and calcium shuttling across the endoplasmic reticulum via SERCA and ryanodine receptors.
Why it matters
It maps the expanding network of non-adrenergic and gut-derived signals controlling mammalian heat production, highlighting alternative thermogenic pathways that function independently of UCP1.
Limits
As a narrative review, it does not use a systematic methodology to evaluate or synthesize studies. Much of the summarized evidence is derived from rodent knockout models and in vitro mechanistic work rather than human clinical investigations.
Cited by
- supports Cold exposure triggers norepinephrine release, which activates uncoupling protein 1 (UCP1) to uncouple mitochondrial oxidative phosphorylation in brown fat and generate heat.