Biochemistry Which of the following substances acts to increase the release of Ca++ from endoplasmic reticulum? A Inositol triphosphate B Parathyroid hormone C 1,25-dihydroxy cholecalciferol D Diacylglycerol 💡 Explanation Which of the following substances acts to increase the release of Ca++ from endoplasmic reticulum? ✓ Correct Answer: A. Inositol triphosphate