What is the primary function of insulin?

• A. To regulate blood glucose levels
• B. To stimulate water reabsorption
• C. To increase metabolism
• D. To trigger ovulation

Answer: (A)

The primary function of insulin is to regulate blood glucose levels. Insulin is a peptide hormone produced by the beta cells of the pancreas and plays a crucial role in glucose metabolism. After food intake, blood glucose levels rise, prompting the pancreas to release insulin. Insulin facilitates the uptake of glucose by cells, particularly in muscle and adipose tissue, allowing these cells to use glucose for energy or store it as glycogen for later use. This mechanism is essential for maintaining homeostasis in blood sugar levels, preventing hyperglycemia (high blood sugar) and supporting overall metabolic function.

Other options refer to different physiological functions. For instance, stimulating water reabsorption is primarily associated with hormones like antidiuretic hormone (ADH). Increasing metabolism involves multiple hormones and processes, with thyroid hormones playing a significant role. Triggering ovulation is mainly driven by luteinizing hormone (LH) in the menstrual cycle context. Each of these functions is important, but they do not relate to insulin's central role in blood glucose regulation.