Acts as a high affinity receptor for both nicotinic acid (also known as niacin and (D-beta-hydroxybutyrate and mediates increased adiponectin secretion and decreased lipolysis through G(i-protein-mediated inhibition of adenylyl cyclase. This pharmacological effect requires nicotinic acid doses that are much higher than those provided by a normal diet. Mediates nicotinic acid-induced apoptosis in mature neutrophils. Receptor activation by nicotinic acid results in reduced cAMP levels which may affect activity of cAMP-dependent protein kinase A and phosphorylation of target proteins, leading to neutrophil apoptosis. The rank order of potency for the displacement of nicotinic acid binding is 5-methyl pyrazole-3-carboxylic acid = pyridine-3-acetic acid > acifran > 5-methyl nicotinic acid = acipimox >> nicotinuric acid = nicotinamide.,HCAR2,GPR109A,HCA2,HM74a,HM74b,NIACR1,PUMAG,Puma-g,Cancer,Tumor suppressors,p53 pathway,Signal Transduction,G protein signaling,G-Protein-Coupled Receptors(GPCR),Cell Biology & Developmental Biology,Apoptosis,Endocrine & Metabolism,Lipid Metabolism,Hydrolysis,Cardiovascular,Lipids,HCAR2