AGT

Agt is the gene symbol most commonly associated with the human gene AGT, which encodes angiotensinogen, a large secreted glycoprotein that serves as the substrate for the renin–angiotensin system. Angiotensinogen is produced primarily by the liver and released into the circulation, where it is cleaved by renin to form angiotensin I and subsequently angiotensin II through the action of angiotensin-converting enzyme. Angiotensin II is a potent vasoconstrictor that stimulates aldosterone secretion and helps regulate blood pressure, electrolyte balance, and fluid homeostasis.

Genetic and molecular characteristics: The AGT gene is situated on chromosome 1 in humans and is expressed broadly, with the highest levels in the liver. The gene produces a preproprotein that is processed to the mature angiotensinogen protein, which circulates in plasma and acts as a key substrate in the endocrine control of vascular tone and renal function. Expression can be influenced by hormonal factors, including glucocorticoids and estrogens, and by nutritional and physiological states.

Genetic variation and clinical relevance: Among the polymorphisms studied, the M235T (rs699) variant in AGT is well known for correlating with higher plasma angiotensinogen levels and has been associated with modestly increased risk of essential hypertension in some populations. Other promoter and coding variants can affect transcription and protein function. Consequently, AGT contributes to individual differences in blood pressure regulation and cardiovascular risk, and its activity is a target of pharmacological therapies that modulate the renin–angiotensin system, such as ACE inhibitors and angiotensin receptor blockers.

In other species, the AGT gene is conserved, and angiotensinogen plays a similar role in maintaining circulatory and fluid balance across mammals.