Answer
Auto-tubuloglomerular feedback is tagged with the prefix "auto-" because "auto" means self and this process takes place completely within the kidneys.
Work Step by Step
There are three sets of processes that regulate renal filtration; one set takes place within the kidneys, but a second set is neural, and a third set is humoral
Glomerular filtration rate (GFR) is adjusted by blood flow in and out of the glomerulus. When blood flow increases, GFR increases; when blood flow decreases, GFR falls. The amount of the area of glomerular capillaries available for for filtration also influences the GFR.
Regulation of GFR is partly autorenal ( within the kidneys), and partly outside the kidneys --neural, and hormonal. Local regulation involves a myogenic mechanism mediated through stretch receptors in blood vessel walls; in addition, there is the tubuloglomerular feedback mechanism. This last process involves detection of increased concentrations of electrolytes by macula densa cells, and the inhibition of nitric acid (NO) release by juxtaglomerular apparatus (JGA) cells ; this functions in the the control of blood pressure and amount of blood flow; it is described by the prefix "auto" because it is a process (negative feedback) that takes place entirely within the kidneys.
