What is one factor that helps to regulate G-cell activity?

G-cells, which are located in the gastric mucosa, primarily secrete gastrin, a hormone that plays a crucial role in the regulation of gastric acid secretion and digestive processes. While various hormones and factors influence digestive activities, secretin is not a primary regulator of G-cell activity.

Gastrin itself is the main factor stimulating G-cells, promoting their secretion when there is food in the stomach, particularly proteins. It enhances gastric motility and promotes the secretion of gastric acid from parietal cells. Furthermore, the activity of G-cells can be modulated indirectly by changes in the pH of the stomach. When the pH is low, gastrin release is inhibited, and when food enters the stomach and raises the pH, gastrin release is stimulated.

Cholecystokinin, on the other hand, mainly influences gallbladder contraction and pancreatic enzyme secretion, while pepsin is an enzyme that aids digestion but does not have a regulatory role over G-cell activity. Knowing these distinctions clarifies why gastrin is the pivotal factor in regulating G-cell function in the digestive system.