And what glucagon does, as we'll see in just a moment, is ultimately increase the concentration of glucose inside our blood. And that means the cells can use that glucose to basically create ATP and use it as an energy source. So we mentioned that glucagon is a peptide hormone and that means it's water soluble and so it can easily dissolve inside our blood and it doesn't need any protein carrier to transport it inside our blood. Now, the fact that our glucagon is a peptide hormone also means it is not lipid soluble. And that means it cannot actually pass across the cell membrane. So what glucagon does is it finds the target cell, which is usually the cell inside the liver, known as the liver cells.