Current HCA receptor nomenclature and receptor properties For further details, see IJzerman et al. (2010).

Previous names/aliasesGPR81, GPR104, TA-GPCR, LACR, FKSG80GPR109A, HM74a (human), PUMA-G (mouse), HM74b, NIACR1GPR109B, HM74, NIACR2
Genomic location12q24.31 (human), 5F (mouse)12q24.31 (human), 5F (mouse)12q24.31 (human)
Amino acid length346 (human), 343 (mouse)363 (human), 360 (mouse)387 (human)
Naturally occurring specific agonists (pEC50)2-OH-propanoate (2.5–2.8)3-OH-butyrate (3.1), nicotinic acid (6.6–7.2)3-OH-octanoate (5.1), 2-OH-octanoate (5.4), D-phenylalanine (5.0), D-tryptophan (5.4)
Specific synthetic agonists (pEC50)acipimox (5.2–5.6)1-Isopropylbenzo-triazole-5-carboxylic acid (6.4), 5-methyl-5-(5-methyl-thio-phen-3-yl)-4-oxo-4,5-dihydro-furan-2-carboxylic acid (6.7)
G-protein couplingGi/GoGi/GoGi/Go
Expression in human tissueAdipocytesAdipocytes, macrophages, neutrophils, epidermal Langerhans cells, keratinocytes, intestinal epithelial cellsAdipocytes, neutrophils, macrophages, intestinal epithelial cells
Cellular functionInhibition of lipolysisInhibition of lipolysis, activation of immune cellsInhibition of lipolysis, activation of immune cells
Phenotype of mice lacking receptorReduced insulin-induced antilipolysisLack of nicotinic acid effects on lipid plasma levels and of nicotinic acid-induced flushing