G protein-coupled receptor for nicotinic acid in mouse macrophages

Molecular Identification of High and Low Affinity Receptors for Nicotinic Acid

“…The murine variant of HM74A, PUMA-G, was recently reported to be an interferon ␥-inducible gene in macrophages, suggesting a possible role in macrophage function (19). This finding is further supported by a recent report describing a nicotinic acid receptor in a murine macrophage cell line (20). Based on the TaqMan data generated for the distribution of human HM74A, there appears to be little or no expression in macrophages (Fig.…”

Niacin-induced “Flush” Involves Release of Prostaglandin D2from Mast Cells and Serotonin from Platelets: Evidence from Human Cells in Vitro and an Animal Model

“…In one of these studies, topical superpharmacological administration of methylnicotinate (10 Ϫ3 -10 Ϫ1 M) on forearms of normal volunteers dramatically increased serum PGD 2 (Morrow et al, 1992). Niacin was shown to stimulate PGD 2 synthase in macrophages (Knowles et al, 2006) through activation of a unique Gprotein-coupled receptor (Lorenzen et al, 2002) and, after 30 min of stimulation, resulted in a 3-fold PGD 2 release from cultured macrophages but not from monocytes or endothelial cells (Meyers et al, 2007). As the authors admitted, these in vitro findings did not reflect the amount of PGD 2 release in vivo or the fact that the niacin flush occurs within a few minutes in humans (Meyers et al, 2007).…”

Effects of a niacin receptor partial agonist, MK-0354, on plasma free fatty acids, lipids, and cutaneous flushing in humans

“…A previously validated Flushing Symptom Questionnaire 19 was completed daily at 8 to 12 hours postdose during the second week of the placebo run-in period (days Ϫ7 to Ϫ1), the first 7 days of active treatment (days 1 to 7), and the last 7 days of active treatment (days 22 to 28). One of the Flushing Symptom Questionnaire questions assessed the intensity of all four flushing symptoms (skin redness, warmth, tingling, and/or itching) in aggregate using an 11-point numerical rating scale, the Global Flushing Severity Score (GFSS), which was labeled with the following intensity categories: none (score of 0), mild (1-3), moderate (4 -6), severe (7)(8)(9), and extreme (10).…”