After a meal, insulin levels ____________ while glucagon levels ____________.

After a meal, insulin levels increase while glucagon levels decrease.

This physiological response is part of the body's regulatory mechanism to maintain blood glucose levels. When food is ingested, glucose from the meal enters the bloodstream, leading to an elevation in blood glucose levels. In response to this increase, the pancreatic beta cells secrete more insulin. Insulin's primary role is to facilitate the uptake of glucose by tissues, especially muscle and adipose tissue, and to promote the storage of glucose as glycogen in the liver.

At the same time, the secretion of glucagon by the pancreatic alpha cells declines. Glucagon serves to increase blood glucose levels by stimulating glycogenolysis (the breakdown of glycogen to glucose) and gluconeogenesis (the production of glucose from non-carbohydrate sources) during periods of fasting. Thus, after a meal when the body's priority shifts to storing and utilizing the incoming glucose, you see a decrease in glucagon secretion as its role diminishes in the presence of high insulin.

This interplay between insulin and glucagon is critical for glucose homeostasis, ensuring that the body efficiently uses and stores nutrients after feeding.