Question

When the plasma glucose concentration rises above about ___mg/dL, it exceeds the renal threshold, the concentration at which the kidneys...

a) 200 mg/dL, reabsorb glucose
b) 300 mg/dL, excrete glucose
c) 100 mg/dL, produce insulin
d) 150 mg/dL, activate glucagon

Answer 1

The renal threshold for glucose, beyond which the kidneys start to excrete glucose in the urine, is generally around 180 mg/100 ml of blood. Exceeding this level leads to glucosuria.

Step-by-step explanation:

When the plasma glucose concentration rises above about 180 mg/dL, it exceeds the renal threshold, the concentration at which the kidneys begin to excrete glucose. This condition is known as glucosuria. The renal threshold for glucose is typically around 180 mg/100 ml of blood. If the glucose concentration in the blood exceeds this value, the filtered glucose that exceeds the transport maximum (Tm) is excreted in the urine. Insulin and glucagon are hormones that regulate blood glucose levels but are not directly related to the renal threshold of glucose.