Endocrinology Practice Questions

Correct Answer: B

Rationale: The correct answer is B: Kidney disease. Oral contraceptive pills are contraindicated in patients with kidney disease due to the risk of impaired drug clearance and potential adverse effects on renal function. Breast cancer (A), liver disease (C), and prior history of deep venous thrombosis (D) are all contraindications to the use of oral contraceptives due to increased risks of complications such as thrombosis or exacerbation of underlying conditions.

Correct Answer: C

Rationale: The correct answer is C: Purple skin striae. This is the most common sign of Cushing's syndrome due to the excessive production of cortisol leading to thinning of the skin and formation of purple stretch marks. Hirsutism (A) is excessive hair growth, not specific to Cushing's. Obesity (B) can be a symptom, but it is not the most common. Skin hyperpigmentation (D) is seen in Addison's disease, not Cushing's.

Correct Answer: C

Rationale: Sertoli cells are responsible for producing and secreting Androgen binding globulin (ABG). They play a crucial role in supporting spermatogenesis by providing structural and nutritional support to developing sperm cells. ABG helps in the transport of testosterone and other androgens within the seminiferous tubules, aiding in the regulation of spermatogenesis. Testosterone is primarily produced by Leydig cells in the testes, not by Sertoli cells, making option A incorrect. Option B, Oestrogen, is mainly synthesized in the ovaries, while Sertoli cells do not produce GnRH (option D), which is secreted by the hypothalamus. Therefore, the correct answer is C, as Sertoli cells are primarily responsible for producing and secreting Androgen binding globulin.

Correct Answer: C

Rationale: The correct answer is C because dipsogenic diabetes insipidus is caused by a defect or damage to the hypothalamus, not the pituitary gland or pituitary stalk. The hypothalamus regulates thirst and water intake, so damage to this area can lead to excessive thirst and dilute urine output characteristic of diabetes insipidus. Choices A and D incorrectly attribute the cause to the pituitary gland or pituitary stalk, which are not directly involved in regulating thirst. Choice B is incorrect as it mentions malfunction of the hunger mechanism, which is not relevant to dipsogenic diabetes insipidus. Thus, choice C is the most accurate definition based on the pathophysiology of the condition.

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.