β-adrenergic stimulation of skeletal muscle HSL can be overridden by AMPK signaling

Abstract

Hormone-sensitive lipase (HSL), an important regulatory enzyme for triacylglycerol hydrolysis within skeletal muscle, is controlled by beta-adrenergic signaling as well as intrinsic factors related to contraction and energy turnover. In the current study, we tested the capacity of 5'AMP-activated protein kinase (AMPK) to suppress beta-adrenergic stimulation of HSL activity. Eight male subjects completed 60 min of cycle exercise at 70% VO2 peak on two occasions: either with normal (CON) or low (LG) pre-exercise muscle glycogen content, which is known to enhance exercise-induced AMPK activity. Muscle samples were obtained before and immediately after exercise. Pre-exercise glycogen averaged 37..