Is PBEF/visfatin/Nampt an authentic adipokine relevant to the metabolic syndrome?

Abstract

Adipokines are peptides secreted by adipose tissue that affect whole-body energy metabolism. Their dysregulated production in obesity has implicated them as important mediators in the pathogenesis of obesity-related risk factors for diabetes and cardiovascular disease. PBEF/visfatin/Nampt has recently been described as a novel adipokine with insulin mimetic properties. However, whether it is an authentic adipokine relevant to the metabolic syndrome remains a matter of some debate.

Figure 1

The central role of NMPRTase (Nampt*) in the salvage pathway for NAD biosynthesis and related cellular functions. ADP—adenosine diphosphate; ATP—adenosine triphosphate; cADPR—cyclic ADP-ribose; NAADP—nicotinic acid-adenine dinucleotide phosphate; NAD—nicotinamide adenine dinucleotide; NADP—nicotinamide adenine dinucleotide phosphate; NAD(P)H—nicotinamide adenine dinucleotide (phosphate), reduced form; Nampt—nicotinamide phosphoribosyltransferase; NMN—nicotinamide mononucleotide; Nmnat—nicotinamide mononucleotide adenylyltransferase; PARP—poly-ADP-ribose polymerase; PPi—inorganic pyrophosphate; PRPP—5-phosphoribosyl-1-pyrophosphate.