Burst-like control of lipolysis by the sympathetic nervous system in vivo

• Published in: The Journal of clinical investigation 2003-01, Vol.111 (2), p.257-264
• Main Author: Hucking, K.
• Format: Article
• Language: English
• ISSN: 0021-9738
• DOI: 10.1172/JCI200314466

Rapid oscillations of visceral lipolysis have been reported. To examine the putative role of the CNS in oscillatory lipolysis, we tested the effects of beta sub(3)-blockade on pulsatile release of FFAs. Arterial blood samples were drawn at 1-minute intervals for 120 minutes from fasted, conscious dogs (n = 7) during the infusion of saline or bupranolol (1.5 mu g/kg/min), a high-affinity beta sub(3)-blocker. FFA and glycerol time series were analyzed and deconvolution analysis was applied to estimate the rate of FFA release. During saline infusion FFAs and glycerol oscillated in phase at about eight pulses/hour. Deconvolution analysis showed bursts of lipolysis (nine pulses/hour) with time-dependent variation in burst frequency. Bupranolol completely removed rapid FFA and glycerol oscillations. Despite removal of lipolytic bursts, plasma FFAs (0.31 mM) and glycerol (0.06 mM) were not totally suppressed and deconvolution analysis revealed persistent non-oscillatory lipolysis (0.064 mM/min). These results show that lipolysis in the fasting state consists of an oscillatory component, which appears to be entirely dependent upon sympathetic innervation of the adipose tissue, and a non-oscillatory, constitutive component, which persists despite beta sub(3)-blockade. The extinction of lipid fuel bursts by beta sub(3)-blockade implies a role for the CNS in the maintenance of cyclic provision of lipid fuels.