The characterization and energetic potential of brown adipose tissue in man

Abstract

In adult man, brown fat can be detected in perinephric fat depots by visual inspection, electron microscopy and nucleotide binding to the tissue-specific uncoupling protein. The 32 kDa uncoupling protein is functionally active, showing a nucleotide-sensitive conductance to protons and an uncoupling response to fatty acids. The amount of uncoupling protein in human mitochondria is equivalent to that in a partially cold-adapted guinea pig, indicating some potential for thermogenesis. Respiratory capacity measurements indicate that the total perinephric fat in adult man can only account for one-fivehundredth of the whole-body response to infused noradrenaline. Thus, although brown fat has been found to be quantitatively important in animal studies, considerable caution must be exercised in extrapolating its significance to adult man.

DNA polymorphism in the uncoupling protein 1 (UCP1) gene has no effect on obesity related phenotypes in the Swedish Obese Subjects cohorts

“…12 In contrast, we found no effect of the ADRB3 mutation on the SOS cohorts. 32 In the present study, we could not replicate the trend previously found with the UCP1 variant in the French cohort of morbidly obese patients 12 and in the QFS family. 10 The previous studies on this UCP1 variant 10 ±13,33 and the present report, are all ®nding allelic frequencies for the UCP1 A-3826G ranging from about 0.24 ± 0.28 with no signi®cant difference between obese subjects and non-obese subjects.…”

Human Brown Adipose Tissue: What We Have Learned So Far

“…Because of findings in rodent models and observations of increased energy expenditure in response to b3-adrenergic agonists (32) and different responses to cold in lean versus obese humans (33), it was speculated that decreased BAT mass and activity might be implicated in the development of obesity and type 2 diabetes (34). At that time it was, however, not possible to unequivocally prove the metabolic activity in human adults (35)(36)(37).…”

Transcriptional control of brown adipocyte development and thermogenesis

“…Although it has been known for many years that adult humans possess BAT in other areas, the consensus was that the mass and/or activity of this tissue was metabolically insignificant. 2,3 However, at present, using modern imaging methods, several reports indicate that most, if not all, healthy adult humans have appreciable amounts of active BAT. [4][5][6][7] The field must now address to what extent natural variations in BAT activity affects energy balance and obesity in adult humans.…”