What is the signal for a vesicle storing peptide hormone to move to the plasma membrane and release contents of vesicle?

a. Activation of an integrin receptor

b. Activation of a g-protein

c. Activation of an enzyme linked receptor

d. Increase in [Ca++]i

e. Increase in [Na+]i

(d). Increase in [Ca++]i

Explanation:

Peptide hormones are hormones, synthesized by polymerization of amino acids that generally bind with receptors present on membrane of target cells. These hormones are produced in ER (endoplasmic reticulum) and are packed into secretory vesicles in Golgi for export.

These peptide hormone storing vesicles move to membrane of target cell and release their content due to increase in intracellular calcium (Ca++) ions concentration.

Thus, the correct answer is option (d).