Which physiological condition is likely to suppress ghrelin secretion after a meal?

• A. Increased levels of circulating glucagon
• B. Decreased osmolarity in the ileum
• C. Increased levels of circulating insulin
• D. Decreased levels of circulating insulin

Answer: (C)

Ghrelin is a hormone produced primarily in the stomach that stimulates appetite and promotes food intake. Its levels typically rise in the fasting state and decrease after a meal. During and after eating, various physiological changes take place, some of which involve the secretion of other hormones that can influence ghrelin levels.

Increased levels of circulating insulin, which occur after a meal as a response to rising blood glucose levels, play a significant role in suppressing ghrelin secretion. Insulin not only helps to lower blood glucose but also communicates to the body that food has been consumed, signaling the brain to reduce hunger. Insulin's action in suppressing ghrelin is an essential feedback mechanism that helps regulate appetite and energy balance.

The other physiological conditions mentioned, such as increased glucagon levels or changes in osmolarity, do not specifically correlate with the suppression of ghrelin in the same clear manner that insulin does. For instance, glucagon, which is secreted in response to low blood sugar, tends to counteract insulin's effects and does not promote the suppression of ghrelin. Similarly, while changes in osmolarity in the ileum can influence other gut hormones, they do not directly suppress ghrelin in the postprand