Question

Which one of the following is not a secondary messenger in hormone action?

(a) cAMP

(b) cGMP

(c) calcium

(d) sodium

Answer 1

Secondary messengers in the intracellular signalling. The activation of adenylyl cyclase is due to the stimulation of hormone Gs coupled receptors. cAMP (cyclic adenosine monophosphate) activates specific protein kinases (cAPKs).

Calcium ions are also act as secondary messengers and secreted into the cytoplasm by endoplasmic reticulum. Thus the prasent of calcium ions triggers the hormone effects in the cell.

cGMP (Cyclic guanosine monophosphate) is also secondary messanger which meditates many cells and tissues. Heart plays a vital role in slows down muscle contraction in response to acetylcholine.

Sodium is the prasent outside the cell and helps to regulate blood pressure and blood volume. It is not secondary messanger in hormone action.

Hence option (d) is correct.