Metformin is preferred over phenformin because:

Correct Answer: B

Rationale: Metformin is preferred over phenformin because it is less liable to cause lactic acidosis. Lactic acidosis is a potentially life-threatening condition characterized by the buildup of lactic acid in the blood. Phenformin, an older biguanide medication similar to metformin, has been associated with a higher risk of causing lactic acidosis compared to metformin. This risk led to the removal of phenformin from the market due to safety concerns. Metformin, on the other hand, has a lower risk of causing lactic acidosis, making it a safer choice for the management of diabetes.

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.

Correct Answer: A

Rationale: Corticosteroid therapy can exacerbate or worsen several medical conditions. However, it typically does not aggravate congenital adrenal hyperplasia (CAH). CAH is a genetic disorder characterized by a deficiency of certain enzymes in the adrenal glands, leading to problems with hormone production. Corticosteroid therapy is actually a key component of the treatment for CAH, helping to replace the deficient hormones and manage symptoms. In contrast, corticosteroid therapy can worsen conditions such as diabetes mellitus, hypertension, and peptic ulcer disease by affecting glucose metabolism, blood pressure regulation, and gastric mucosal integrity, respectively.