Notes: Nicotinic acid, also known as niacin, is an antagonist of hydroxycarboxylic acid receptor 2 (HCA2), known previously as GPR109A (Ki = 113 nM).{65651} Nicotinic acid reduces lipolysis in primary human adipocytes (IC50 = 200 nM).{65653} It reduces the invasion of AH109A-TC cancer cells when used at concentrations of 20 and 40 µM.{65652} Nicotinic acid increases cutaneous vasodilation in normotensive mice in a dose-dependent manner.{15245} Formulations containing nicotinic acid have been used in the treatment of hyperlipidemia.