The insulin preparation of choice in diabetic ketoacidosis is:

Correct Answer: A

Rationale: Regular insulin is the preferred choice for the treatment of diabetic ketoacidosis (DKA) due to its rapid onset of action. Regular insulin is a short-acting insulin that can be started as an intravenous infusion for quicker correction of elevated blood glucose levels in DKA. It helps to reduce ketone production and promotes the uptake of glucose by cells, thus addressing both the hyperglycemia and ketosis seen in DKA.

Correct Answer: A

Rationale: Metformin, a commonly used medication for the management of type 2 diabetes, primarily works by decreasing glucose production in the liver and improving insulin sensitivity in muscle cells. In individuals without diabetes (nondiabetics), there is typically no significant effect on blood sugar levels since their bodies are already functioning properly in terms of glucose regulation. Therefore, metformin would cause little to no lowering of blood sugar levels in nondiabetic individuals.

Correct Answer: C

Rationale: Thiazolidinediones, such as pioglitazone and rosiglitazone, are primarily used as an adjunctive therapy in type 2 diabetes mellitus. They work by decreasing insulin resistance in the body, thus helping to improve blood sugar control. Thiazolidinediones are typically prescribed in combination with other oral antidiabetic medications like sulfonylureas or biguanides to achieve better glycemic control. They are not commonly used as the sole drug in type 1 diabetes mellitus, as their mechanism of action is more beneficial for type 2 diabetes. Thiazolidinediones are not usually used as adjunctive therapy with insulin in type 1 diabetes as well.

Correct Answer: C

Rationale: Hydrocortisone is a glucocorticoid hormone that affects the regulation of electrolyte balance in the body. In the kidneys, hydrocortisone acts to increase the excretion of potassium (K+) while also enhancing the reabsorption of calcium (Ca2+). This results in a decrease in potassium levels in the blood (hypokalemia) and an increase in calcium levels (hypercalcemia). Therefore, the correct action of hydrocortisone is to decrease potassium excretion and increase calcium excretion.

Correct Answer: D

Rationale: The glucocorticoid receptor is a type of nuclear receptor that is located inside the nucleus of the cell. Upon activation by the binding of glucocorticoid hormones (such as cortisol), the glucocorticoid receptor translocates into the nucleus from the cytoplasm. Inside the nucleus, the activated glucocorticoid receptor regulates gene expression by binding to specific regions of DNA known as glucocorticoid response elements. This interaction leads to the modulation of various cellular processes and physiological responses controlled by glucocorticoid signaling. Therefore, the correct location of the glucocorticoid receptor is inside the nucleus.