Beta-adrenergic stimulation of fatty acid release from brown fat cells differentiated in monolayer culture.

The ability of brown adipocytes differentiated in monolayer culture to respond to norepinephrine was investigated. It was found that fatty acid release in confluent brown adipocytes in monolayer culture was induced by norepinephrine, thus these cells were hormone-sensitive. After confluence, the rate of fatty acid release successively declined. The norepinephrine-stimulated fatty acid release was inhibited by propranolol, but not by phentolamine, indicating a mediation via beta-adrenergic receptors. It was concluded that there exist in the brown adipose tissue of nonfetal rats preadipocytes which possess the ability to express in culture a fully developed beta-adrenergic lipolytic response.