Question

A person passes much urine and drinks much water but his blood glucose level is normal. This condition may be the result of:

• A. A reduction in insulin secretion from pancreas
• B. A reduction in vasopressin secretion from posterior pituitary
• C. A fall in the glucose concentration in urine
• D. An increase in secretion of glucagon

Answer 1

The correct option is B

A reduction in vasopressin secretion from posterior pituitary

The correct option is B:

Explanation of the correct option :

1. When a person passes more urine and drinks more water and his blood glucose level is normal, he is suffering from diabetes insipidus.
2. Diabetes insipidus is caused by a reduction in vasopressin hormone, which is secreted from the posterior pituitary gland.
3. Antidiuretic hormone (ADH) maintains and regulates water balance through water reabsorption.
4. Therefore there is a reduction in vasopressin secretion from the posterior pituitary.

Explanation of the incorrect option:

Option A:

Reduction in insulin causes diabetes.

Option C:

A fall in the glucose concentration in urine cause glycosuria because there is not enough insulin.

Option D:

Glucagon is an antagonist of insulin hormone whose secretion is stimulated by a fall in the blood glucose level or a rise in the blood levels. Most of the biological consequences of glucagon lead to an increase in the blood level of glucose.

Final answer: A person passes much urine and drinks water but his blood glucose level is standard. This is caused by a reduction in vasopressin secretion from the posterior pituitary.