GIP and pulmonary arterial hypertension: The pathophysiology underlying PPH remains incompletely understood, but emerging evidence has revealed the fundamental role of gastrointestinal function in the regulation of cardiovascular responses to a meal [1], particularly the secretion and action of gut-derived peptides including glucagon-like peptide-1 (GLP-1) [3], glucose-dependent insulinotropic polypeptide (GIP) [4,5] and somatostatin [6].