A healthy pancreas secretes glucagon into the blood between meals and insulin right after a meal.
Glucagon and insulin have opposite effects on the blood glucose levels (insulin decreases it, glucagon increases it). During digestion, foods that contain carbohydrates are converted into glucose, so the blood glucose levels are high after a meal. This increase in blood glucose signals pancreas to produce insulin which then stimulates the movement of glucose from the bloodstream into the cells. Some of those cells use the glucose as energy while other (in liver and muscles), store it as glycogen. Between the meals. the glucose levels in blood decrease, which triggers the pancreas to produce glucagon that stimulates the break down of glycogen into glucose.