Which hormone is crucial for regulating blood sugar levels?

• A. Adrenaline
• B. Cortisol
• C. Insulin
• D. Thyroxine

Answer: (C)

Insulin is a hormone produced by the pancreas that plays a vital role in regulating blood sugar levels. When blood sugar levels rise after eating, insulin is released into the bloodstream, facilitating the uptake of glucose by cells for energy or storage as glycogen in the liver and muscles. This process helps to lower blood sugar levels to a normal range.

Insulin not only aids in maintaining blood sugar homeostasis but also influences various metabolic processes, including lipid and protein metabolism. Its primary function is to ensure that the body's cells have sufficient energy to function properly, making it a key player in metabolism and energy balance.

In contrast, adrenaline, cortisol, and thyroxine, while important hormones in their own right, do not have the same direct role in blood sugar regulation as insulin does. Adrenaline primarily prepares the body for a 'fight or flight' response and may actually raise blood sugar levels. Cortisol, a stress hormone, can increase blood sugar levels over time if chronically elevated, while thyroxine mainly influences the body's metabolic rate but not directly blood sugar control. Thus, insulin stands out as the fundamental hormone responsible for maintaining stable blood glucose levels.