This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gastrointestinal System, Subject name: Physiology
Appetite is increased by: 
Select and explain. 
A. Leptin, B. Peptide YY, C. Ghrelin, D. Cholecystokinin
C: Ghrelin
Answer: C: Ghrelin 
Explanation: Decrease Feeding (Anorexigenic) Increase Feeding (Orexigenic) a-Melanocyte-stimulating hormone Neuropeptide Y Leptin produced by adipocytes (leptin resistance is associated with obesity) Agouti related protein Serotonin Melanin concentrating hormone Norepinephrine Orexins A and B Coicotropin-releasing hormone Endorphins Insulin Galanin Cholecystokinin Amino acids (glutamate and GABA) Glucagon like peptide Coisol Cocaine- and amphetamine-regulated transcript Ghrelin (released mainly by the oxyntic cells of the stomach) Peptide YY Endocannabinoids