For example, they can open up a channel protein that will change an ion concentration, or they can basically use some type of secondary messenger system that uses some type of secondary messenger, such as cyclic amp, to create some form of change. Now, the second type of hormone that we're going to discuss is our steroid hormone. Now, the steroid hormone is basically synthesized from cholesterol or from some type of lipid. And now steroid hormone is synthesized either in the smooth endoplastic reticulum or in the mitochondria of the cell. Now, steroid hormones are lipid soluble, and that means they cannot dissolve in the blood. And so they actually require carrier proteins to carry them to their target cell.