Select the incorrect statement from the following.

Androgens play a major stimulatory role in the process of spermatogenesis. 

Catecholamines stimulate the breakdown of glycogen resulting in an increased concentration of glucose in blood.

Secretin acts on islets of Langerhans and stimulates secretion of water and bicarbonate ions. 

Water-soluble hormones generate second messengers which in turn regulate cellular metabolism.