<prompt> Which one of the following acts to increase the release of Ca2 from endoplasmic reticulumInositol triphosphateParathyroid hormone1,25 - dihydroxy choleciferolDiacyglycerol  <response>: Ans. a Inositol triphosphateRef: Ganong, 25th edp. 116Inositol triphosphate acts on the sarcoplasmic reticulum to release calcium ions 