In the absence of any regulatory mechanisms what effect do you think an increase in blood pressure would have on glomerular filtration rate?

Answer 1

Generally speaking, it would increase.

However, it depends on the reason for the hypertension. For instance, if there is an obstruction or constriction of the renal artery (stenosis, malignancy, etc...) the physiologic affect would to increase the body's BP. This is due to the fact that the obstruction is decreasing hydrostatic pressure to the glomerulus, and transiently decreasing GFR. The body compensates by increasing BP to increase GFR. Patients that present with a renal artery stenosis could in fact be hypertensive with a decreased GFR.

Answer 2

The rate of GFR will increase if the blood pressure increases, and will decrease if the plasma oncotic pressure increases.

GFR=certain coefficient*arteriolar hydrotstatic pressure - (arteriolar oncotic pressure + glomerular hydrostatic pressure).

Now, to put it very simply the arteriolar hydrostatic pressure is what the mean blood pressure in the afferent arteriole, so if it increases the GFR is bound to increase.