UWorld Endocrine Practice Test

A deficiency of insulin leads to diabetes mellitus, a condition characterized by elevated blood glucose levels due to the body's inability to produce sufficient insulin or respond effectively to it. Insulin is a hormone produced by the pancreas that plays a crucial role in glucose metabolism, allowing cells to take up glucose from the bloodstream and use it for energy or store it as glycogen. When insulin is deficient or absent, glucose remains in the bloodstream, resulting in hyperglycemia.

Diabetes mellitus encompasses several types, the most common being type 1 diabetes, where the body's immune system attacks insulin-producing beta cells in the pancreas, leading to a complete insulin deficiency. Type 2 diabetes typically involves insulin resistance alongside relative insulin deficiency. Regardless of the type, the core issue is the inadequate action of insulin in regulating glucose levels.

The other conditions listed do not stem from insulin deficiency. Hypoglycemia is characterized by low blood sugar levels, which can occur due to excessive insulin rather than a deficiency. Metabolic syndrome is a cluster of conditions such as high blood pressure, high blood sugar, and excess body fat around the waist but isn't directly caused by insulin deficiency. Cushing's syndrome involves excess cortisol levels, which affect glucose metabolism but are unrelated to insulin production. Thus, the correct