Endocrinology Practice Questions

Correct Answer: C

Rationale: The correct answer is C: Stress. Stress triggers the release of growth hormone through the activation of the hypothalamic-pituitary-adrenal axis. When the body is under stress, the hypothalamus signals the pituitary gland to release growth hormone. This hormone then stimulates growth and cell reproduction. Glucocorticoids (A) and somatostatin (B) actually inhibit the release of growth hormone. Obesity (D) can lead to decreased growth hormone release due to disrupted hormonal regulation. In summary, stress is the correct answer as it directly stimulates the release of growth hormone, while the other choices inhibit or have a negative impact on growth hormone release.

Correct Answer: D

Rationale: The correct answer is D: second messengers. Protein hormones typically bind to cell surface receptors, activating second messenger systems to relay the signal inside the cell. This mechanism allows for rapid and amplified cellular responses. Choices A and B (cytoplasmic and nuclear receptors) are more commonly associated with steroid hormones, not protein hormones. Choice C (cyclic ribosomal adenosine phosphate) is not a known mechanism of hormone action. Thus, the correct answer is D, as second messengers are the primary mediators of protein hormone actions.

Correct Answer: D

Rationale: The correct answer is D: Thyroxine-binding globulin (TBG). TBG is the primary source of bound T4 in the plasma as it specifically binds to and transports thyroid hormones. This protein has the highest affinity for T4 compared to other plasma proteins. Albumin (A) and gamma globulins (B) can also bind to thyroid hormones, but TBG is the primary carrier. Thyroid peroxidase (C) is an enzyme involved in thyroid hormone production, not in binding T4 in the plasma.

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: Step-by-step rationale for why answer B is correct: 1. Cushing's syndrome is characterized by excess cortisol production. 2. Women are more likely to develop Cushing's syndrome due to hormonal differences. 3. Women have higher cortisol levels naturally, making them more susceptible. 4. Men can still develop Cushing's syndrome but at a lower rate compared to women. Summary: A: Incorrect, as women are more likely to develop Cushing's syndrome. C: Incorrect, as the incidence is higher in women due to hormonal factors. D: Incorrect, as it refers to thyroid hormones, not cortisol in Cushing's syndrome.