[Physiological and pathophysiological features of the control of lipolysis and lipid mobilization by natriuretic peptides].

We have demonstrated a potent and specific lipolytic effect of natriuretic peptides (NP) in human and primates' fat cells. The lipolytic effect of NP is mediated through intracellular production of cGMP and activation of the cGMP-dependent kinase 1alpha. Local infusion of atrial-NP (ANP), directly within the subcutaneous adipose tissue through a microdialysis catheter, increases lipolysis and stimulates blood flow through its vasodilating effect in lean healthy men. This effect is blunted in overweight men and can be recovered by endurance training. Intravenous infusion of physiological doses of ANP induces lipid mobilization. Higher concentrations of ANP that are encountered during heart failure also stimulate lipid oxidation. ANP activates lipolysis and free fatty acids release from adipose tissue during endurance exercise. This effect is paradoxically amplified when exercise is performed under beta-blockade treatment, because of an enhanced cardiac release of ANP. No gender differences in ANP-induced lipid mobilization during exercise have been found. Heart failure is associated with high circulating levels of NP that could participate to the progression toward cachexia. On contrary, a negative correlation between NP levels and body mass index is found in obese persons. The molecular basis of this inverse correlation is not yet demonstrated from a functional standpoint. Further studies are needed to clearly define the pathophysiological role of NP in obesity and heart failure.