All of the following represent examples of hypothalamic-pituitary negative feedback except:

Correct Answer: D

Rationale: The renin-angiotensin-aldosterone axis does not involve the hypothalamus or pituitary gland; instead, it primarily involves the kidneys and the renin-secreting cells. In this axis, renin is released in response to low blood pressure, leading to the formation of angiotensin II and the subsequent release of aldosterone from the adrenal glands. Feedback mechanisms for this axis primarily involve the regulation of renin release based on blood pressure rather than involving direct negative feedback from downstream hormones on the hypothalamus or pituitary gland. On the other hand, choices A, B, and C all involve classic examples of hypothalamic-pituitary negative feedback loops where the end hormone suppresses the release of the stimulating hormones at the hypothalamic and pituitary levels.

Correct Answer: B

Rationale: ADH (antidiuretic hormone), also known as vasopressin, is secreted by the posterior lobe of the pituitary gland. ADH plays a key role in regulating water balance in the body by controlling the reabsorption of water in the kidneys. When the body senses a decrease in blood volume or an increase in blood osmolarity, ADH is released to signal the kidneys to conserve water, leading to concentrated urine production and water retention in the body.

Correct Answer: B

Rationale: Prolactin levels can be increased by various factors, including chest wall trauma, pregnancy, and renal failure. However, hyperthyroidism is not typically associated with elevated prolactin levels. In fact, hyperthyroidism is more commonly associated with decreased levels of prolactin due to the inhibitory effect of thyroid hormones on prolactin secretion. Therefore, all of the options except for hyperthyroidism would be expected to increase prolactin levels.

Correct Answer: C

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: B

Rationale: Cushing's syndrome is a disorder caused by prolonged exposure to high levels of cortisol hormone. While Cushing's syndrome can manifest with a variety of symptoms, peripheral neuropathy is not a typical feature of this condition. Cushing's syndrome is commonly associated with symptoms such as hirsutism (excessive hair growth), purple striae (skin stretch marks that are purple in color), and acne due to the hormonal imbalances it creates. Peripheral neuropathy, which involves damage to the peripheral nerves leading to symptoms like numbness, tingling, and weakness in the extremities, is not a characteristic symptom of Cushing's syndrome.