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Prolonged use of lithium to treat bipolar disorder can cause damage to the kidne

ID: 219681 • Letter: P

Question

Prolonged use of lithium to treat bipolar disorder can cause damage to the kidneys such that epithelial cells of the collecting duct cannot insert aquaporin channels in their membranes. Which one of the following symptoms would you least expect in a person with such kidney damage? Could you explain how you got the answer?

polyuria (excessive urine production)

polydipsia (frequent drinking)

excessive thirst

high levels of vasopressin secretion

glucosuria (glucose in the urine

A.

polyuria (excessive urine production)

B.

polydipsia (frequent drinking)

C.

excessive thirst

D.

high levels of vasopressin secretion

E.

glucosuria (glucose in the urine

Explanation / Answer

Answer: Option E is correct.

Explanation: Glucose reabsorption mainly takes place in the proximal tubule region of the nephron. It is reabsorbed in active transport system (Glucose-Na cotransporter system) irrespective of the concentration gradient.

So, reduced number of aquaporins in the collecting tube membrane should not be a direct concern for glucose reabsorption. Hence, glucosuria may not be observed.