Aldosterone:

Correct Answer: A

Rationale: Aldosterone increases potassium excretion by promoting the reabsorption of sodium and water in the kidneys, leading to potassium excretion. This helps maintain electrolyte balance. Other choices are incorrect because aldosterone does not directly increase water loss, is released in response to low blood volume, and is deficient in Addison's disease.

Correct Answer: C

Rationale: The correct answer is C: Oxytocin. The anterior pituitary gland produces several hormones, including adrenocorticotropic hormone (A), growth hormone (B), and thyroid-stimulating hormone (D). Oxytocin is actually produced by the posterior pituitary gland, not the anterior pituitary. Oxytocin is responsible for uterine contractions during childbirth and milk ejection during breastfeeding. Therefore, C is the correct answer as it is not produced by the anterior pituitary unlike the other hormones mentioned.

Correct Answer: C

Rationale: The correct answer is C: Ischaemic heart disease. Metabolic syndrome X consists of a cluster of conditions, including hyperlipidemia, obesity, hypertension, and insulin resistance. Ischaemic heart disease, while commonly associated with metabolic syndrome X due to the increased risk factors, is not a direct component of the syndrome itself. Therefore, it is not considered a part of metabolic syndrome X. Hyperlipidemia (A), obesity (B), and hypertension (D) are all key components of metabolic syndrome X due to their association with insulin resistance and increased risk of cardiovascular disease.

Correct Answer: B

Rationale: The correct answer is B: Intranasal vasopressin may be helpful. In diabetes insipidus, there is a deficiency of vasopressin leading to excessive urination and thirst. Administering vasopressin intranasally can help replace the deficient hormone, reducing urine output and thirst. Hypernatremia (choice A) can occur due to excessive water loss, but it is not always present. There is no osmolar gap (choice C) in diabetes insipidus. Urine specific gravity (choice D) is typically low in diabetes insipidus due to the dilute urine produced.

Correct Answer: B

Rationale: The correct answer is B: Chronic pancreatitis. Hypoglycemia is not typically associated with chronic pancreatitis as it is more related to pancreatic insufficiency and impaired glucose regulation. A: Glycogen storage disease can lead to hypoglycemia due to the inability to properly release stored glucose. C: Galactosaemia can cause hypoglycemia due to the impaired breakdown of galactose into glucose. D: Post-gastrectomy can lead to hypoglycemia due to rapid glucose absorption and altered hormonal responses.