Sincalide also called CCK-8 has a molecular formula of C49H62N10O16S3 Sincalide corresponds to the C-terminal octapeptide of cholecystokinin (CCK) which acts on receptors within the gallbladder wall causing it to contract. Cholecystokinin (CCK) is a hormone originally isolated from porcine intestinal mucosa and described as a linear 33-amino acid peptide containing a sulfated tyrosine, which is essential for its biological activity. It has been found in mammals in both the digestive tract and the central nervous system. Among its multiple biological functions, this hormone stimulates pancreatic exocrine secretion, gallbladder contraction, and intestine motility and may also act as a neurotransmitter/neuromodulator in the central nervous system.