Multiple choice Which of the following pairs is not correctly matched? Calcitonin : Parafollicular cell (source) Glucagon : Beta cells (source) MSH : Melanogenesis (function) Insulin : Diabetes mellitus (disease) Melatonin : Maintains sleep-wake cycle (function) Reveal answer Fill a bubble to check yourself B Correct answer Explanation Glucagon is a peptide hormone, produced by alpha cells of the pancreas. Insulin is a peptide hormone synthesized, packaged and secreted in pancreatic beta cells.