Cholecystokinin (CCK) is a peptide hormone found predominantly in the gastrointestinal tract and throughout the central nervous system (CNS), and which has been also shown to stimulate the secretion of calcitonin, insulin and glucagon and to act as a natriuretic kidney peptide. Researchers from Harvard University and affiliated organizations aimed to assess the function of CCK in obesity-induced airway hyperresponsiveness (AHR) and asthma.