Research
Hormonal
Beta-3 adrenergic receptors are not strictly required for brown adipose tissue function or thermogenesis, as evidenced by species lacking them (guinea pigs) or mice genetically ablated for beta-3 receptors, which compensate via beta-1 receptors.
You do not need beta-3 receptors to activate brown fat. The body can use beta-1 receptors to achieve the same thermogenic result if beta-3 receptors are absent or non-functional.
StrongRefutesVERY_HIGH confidence
In this respect, it is noteworthy that the guinea pig lacks identifiable, functional beta-3-receptors in brown adipose tissue... but its brown adipose tissue is nonetheless fully functional... Similarly, brown adipocytes prepared from animals in which the beta-3-gene has been ablated are fully functional, except that in these cells, it is the beta-1-adrenoceptor that mediates the beta-response.
Why this rating
Supported by knockout mouse models and comparative physiology (guinea pigs).
Source
Brown Adipose Tissue: Function and Physiological Significance
Barbara Cannon et al. · Physiological Reviews · 2004
DOI 10.1152/physrev.00015.2003
narrative_reviewCited 6,368×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
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