Correct Answer: A

Rationale: Hypertonicity (increased osmolarity or high concentration of solutes in the blood) is the most potent stimulus for the hypothalamic production of arginine vasopressin (also known as antidiuretic hormone or ADH). When the body senses increased plasma osmolality, the osmoreceptors in the hypothalamus stimulate the release of vasopressin from the posterior pituitary gland. Vasopressin acts on the kidneys to increase water reabsorption and decrease urine output, helping to restore normal osmolarity. This mechanism helps to conserve water and maintain body fluid balance in response to dehydration or increased solute concentration in the blood.

Correct Answer: A

Rationale: Hyperthermia is not a typical feature of diabetic ketoacidosis (DKA). DKA is typically characterized by high blood sugar levels, ketone accumulation, metabolic acidosis, dehydration, drowsiness, and, in severe cases, unconsciousness. Common symptoms include drowsiness, dehydration, and air hunger (deep and rapid breathing). However, hyperthermia, which refers to an elevated body temperature, is not a characteristic typically associated with DKA. It is important to monitor and manage DKA promptly as it is a serious complication of diabetes that requires immediate medical attention.

Correct Answer: D

Rationale: Binding proteins are essential in transporting hormones through the bloodstream and protecting them from rapid degradation by enzymes. These proteins do not actually mediate the hormonal effects themselves. Hormonal effects are typically mediated by the hormone-receptor interactions at target cells. Binding proteins primarily serve as carriers for hormones and maintain their stability and availability in the circulation.

Correct Answer: C

Rationale: Polycystic ovarian disease, also known as polycystic ovary syndrome (PCOS), is a common endocrine disorder characterized by increased levels of androgens (male hormones) and disrupted estrogen production in the ovaries. The hormonal imbalance seen in PCOS leads to increased gonadal production of estrogen. This condition is often associated with symptoms such as irregular menstrual cycles, infertility, acne, and excess facial or body hair growth. In contrast, the other options do not typically involve increased gonadal production of estrogen as seen in PCOS.

Correct Answer: B

Rationale: Hemoglobin A1c, also known as HbA1c or glycated hemoglobin, is a blood test that measures the average blood glucose level over the previous 2 to 3 months. This test is useful in monitoring long-term blood glucose control in individuals with diabetes. Hemoglobin A1c provides an indication of how well blood glucose levels have been controlled over time, reflecting the average blood sugar levels during the lifespan of red blood cells, which is typically around 2 to 3 months. A higher Hemoglobin A1c level indicates poorer blood glucose control and an increased risk of diabetes complications.