Ghrelin growth hormone secretagogue receptor, with the "GHS-R1b" splice being inactive) is involved in mediating a wide variety of biological effects of ghrelin, including: stimulation of growth hormone release, increase in hunger, modulation of glucose and lipid metabolism, regulation of gastrointestinal motility and secretion, protection of neuronal and cardiovascular cells, and regulation of immune function. They are present in high density in the hypothalamus and pituitary, on the vagus nerve (on both afferent cell bodies and afferent nerve endings) and throughout the gastrointestinal tract. Ghrelin promotes intestinal cell proliferation and inhibits apoptosis during inflammatory states and oxidative stress. It also suppresses
Counterregulatory hormone rise in blood concentrations of these counterregulatory hormones is dependent upon both exercise intensity and duration, and is proportional to the rate of glucose uptake by the contracting skeletal muscle. Similarly, the natriuretic peptides counterregulate against renin, angiotensin, and aldosterone which elevate blood pressure. In the reproductive system, inhibins and follistatin counterregulate activins, to control follicle-stimulating hormone and so the release of gonads. Inhibins and activins also regulate bone mass. Counterregulatory hormone A counterregulatory hormone is a hormone that opposes the action of another. The action of insulin is counterregulated by glucagon, epinephrine (adrenaline), norepinephrine (noradrenaline), cortisol, and growth hormone.