A counterregulatory hormone is a hormone that opposes the action of another.
The action of insulin is counterregulated by glucagon, adrenaline (epinephrine), noradrenaline (norepinephrine), cortisol, and growth hormone. These counterregulatory hormones—the term is usually used in the plural—raise the level of glucose in the blood by promoting glycogenolysis, gluconeogenesis, ketosis, and other catabolic processes. In healthy people, counterregulatory hormones constitute a principal defense against hypoglycemia, and levels are expected to rise as the glucose falls. Persistent elevation of a counterregulatory hormone can reduce a person's sensitivity to insulin.
Similarly, the natriuretic peptides counterregulate against renin, angiotensin, and aldosterone which elevate blood pressure.[1]
In the reproductive system, inhibins and follistatin counterregulate activins, to control follicle-stimulating hormone and so the release of gonads.[2] Inhibins and activins also regulate bone mass.[3]