Thermogenesis and brown fat: relevance to human obesity

Brown adipose tissue (BAT) is a specialized thermogenic tissue, which is highly vascularized and richly innervated with sympathetic nerves. Due to the high thermogenic capacity (500 W/kg) even very small quantities such as those found in adult man can significantly influence het production. As little as 50 g BAT could make a contribution of 10-15% to energy turnover in man. This would be more than sufficient to cause large differences in fat deposition between individuals with active or inactive dietary induced thermogenesis. Recent research has revealed the presence of an atypical beta-adrenoreceptor on BAT, tentatively designated as beta 3-adrenoreceptor. The development of beta 3-agonists offers an opportunity to treat obesity without the cardiovascular and other undesirable side-effects of conventional adrenergic agonists.