Which hormone is released by the pancreas and helps to either usher glucose into cells or store it as glycogen when blood sugar levels are high?

Insulin is a critical hormone released by the pancreas in response to elevated blood sugar levels. When you consume carbohydrates, glucose enters the bloodstream, prompting the pancreas to secrete insulin. This hormone functions by facilitating the uptake of glucose into cells, allowing them to use this sugar for energy. Additionally, insulin encourages the storage of glucose in the liver and muscles in the form of glycogen, thereby lowering blood sugar levels back to a homeostatic state.

The importance of insulin in regulating blood sugar cannot be overstated, as it plays a vital role in maintaining energy balance and overall metabolic health. Conditions such as insulin resistance or diabetes occur when this regulatory mechanism is impaired, leading to chronic high blood sugar levels.

The other hormones listed do not fulfill this specific role. For instance, leptin is primarily involved in regulating energy balance and body weight by inhibiting hunger, while ghrelin stimulates appetite. Glucagon, on the other hand, acts in opposition to insulin by raising blood sugar levels when they are low, primarily by promoting the release of glucose from glycogen stores. The distinct function of insulin in managing high blood sugar makes it the correct answer to this question.