Brain Insulin Controls Adipose Tissue Lipolysis and Lipogenesis

SummaryWhite adipose tissue (WAT) dysfunction plays a key role in the pathogenesis of type 2 diabetes (DM2). Unrestrained WAT lipolysis results in increased fatty acid release, leading to insulin resistance and lipotoxicity, while impaired de novo lipogenesis in WAT decreases the synthesis of insulin-sensitizing fatty acid species like palmitoleate. Here, we show that insulin infused into the mediobasal hypothalamus (MBH) of Sprague-Dawley rats increases WAT lipogenic protein expression, inactivates hormone-sensitive lipase (Hsl), and suppresses lipolysis. Conversely, mice that lack the neuronal insulin receptor exhibit unrestrained lipolysis and decreased de novo lipogenesis in WAT. Thus, brain and, in particular, hypothalamic insulin action play a pivotal role in WAT functionality.

► Insulin signaling suppresses lipolysis by reducing sympathetic output to fat tissue
► Neuronal insulin signaling induces de novo lipogenesis in adipose tissue
► Impairment of hypothalamic insulin signaling unrestrains adipose tissue lipolysis