Plasma membrane involvement in brown fat thermogenesis.

Recent experiments indicate that plasma membranes of brown adipocytes contain distinct alpha- and beta-adrenergic receptors able to recognize norepinephrine. Although activation of either receptor leads to brown fat thermogenesis via pathways that have some, but not all, events in common, the beta-induced calorigenesis appears quantitatively greater than that elicited by the alpha-pathway. The sensitivity of the adrenergic-evoked respiration to Na+/K+ pump blockade as well as to atractyloside supports the view that a significant portion of brown fat thermogenesis reflects increased ATP turnover and enhanced mitochondrial ATP synthesis.