What gas plays a major role in humoral regulation?

Let’s start by remembering what humoral regulation is.

Humoral regulation is a process that regulates the body’s vital processes through the fluids in it (blood, lymph, and so on).

Our question, apparently, concerns the humoral regulation of respiration processes. And that gas is carbon dioxide. It can be written as a chemical formula as CO2. With an increase in its concentration in the blood, the excitability of the respiratory center increases and it becomes more frequent. And when it decreases, the opposite is true.