Angiotensin juxtaglomerular apparatus

Sympathetic stimulation of adrenergic receptors on the granular cells of the juxtaglomerular apparatus promotes secretion of renin and, consequently, formation of angiotensin II. Angiotensin II then causes ... 

Specialized cells, called the juxtaglomerular apparatus (JGA), within the renal cortex are able to detect a fall in blood pressure and respond by secreting a proteolytic enzyme called renin (not to be confused with rennin). The substrate for renin, a liver-derived peptide called angiotensinogen, circulates in the plasma. Renin removes two amino acids from the N-terminal to produce angiotensin I, which is itself a substrate for angiotensin-converting enzyme (ACE). ACE removes two more amino acids to produce angiotensin II. 

The novel endocrine glands are the skin, gastrointestinal tract, adipose tissue, kidney (juxtaglomerular apparatus in the cortex which secretes renin that indirectly controls aldosterone secretion, via angiotensin-11), pineal gland, which secretes melatonin, and the heart (cardiac myocytes in the atria, which secrete atrial natriuretic peptide). 

The renin angiotensin response to trauma has been investigated in some detail in reference to its controlling action on aldosterone (C9). Experimental studies in animals suggested that nerve impulses act directly on the juxtaglomerular apparatus to release renin. An intramuscular injection of sterile saline in unanesthetized rats produced an increase in plasma renin (B9). After extensive burns in man very high levels of renin were found. A detailed study on the effects of anesthesia,... 

Renin is an enzyme of the hydrolase class that catalyzes cleavage of the leucine-leucine bond in angiotensinogen to generate angiotensin I. The enzyme is synthesized as inactive prorenin in the kidney and released into the blood in the active form in response to various metabolic stimuli. The importance of renin in the maintenance of systemic blood pressure was discussed previously (see Juxtaglomerular Apparatus). 

Juxtaglomerular Apparatus Renin-Angiotensin System Mode of Action of Aldosterone... 

---