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HCAR2 historically GPR109A/HM74A in humans; mouse receptor PUMA-G. The location of the responsible immune cells was inferred, not every human flush directly measured.\nexposure: Nicotinic acid; receptor or cyclooxygenase deletion; wild-type bone-marrow rescue\ncross_nutrient: Prostaglandin E2 (additional_signal); Nicotinic acid (trigger)\nevidence_span: {\"source_cache\": \"artifacts/niacin-clinical-sources/benyo2005.abstract.txt\", \"locator\": \"Indexed primary abstract\", \"file_sha256\": \"21dedb52cbd8fccaf810dabec7837e471525e0a5462827b21437d2f7b30c44a2\", \"start_char\": 0, \"end_char\": 1388, \"text_sha256\": \"21dedb52cbd8fccaf810dabec7837e471525e0a5462827b21437d2f7b30c44a2\"}\n[nia-clin-benyo2005] GPR109A (PUMA-G/HM74A) mediates nicotinic acid-induced flushing. 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