Glucose entry into the cells of the following organ/tissue is highly dependent on the presence of insulin:

Correct Answer: C

Rationale: Glucose entry into adipose tissue cells is highly dependent on the presence of insulin. Insulin plays a crucial role in promoting glucose uptake by inducing the translocation of glucose transporter proteins, particularly GLUT4, to the cell membrane of adipose tissue cells. This process allows the cells to take up glucose from the bloodstream, thereby regulating blood glucose levels. In the absence of insulin or in conditions of insulin resistance, such as in diabetes, glucose uptake by adipose tissue is impaired, leading to hyperglycemia.

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: 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: 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.