A group of researchers is looking into why people who have had a gastrectomy lose more weight than can be explained by dietary changes alone. They recruit several subjects for a clinical study who have had distal gastrectomy for benign gastric-outlet obstruction. Control subjects with similar baseline weights are also enrolled and instructed to follow a diet similar to the postgastrectomy subjects during the study period. In both groups, plasma levels of several hormones are measured serially over a 24-hour period. Levels of one of the hormones are shown in the graph below: This profile most likely represents which of the following hormones?

Question

A group of researchers is looking into why people who have had a gastrectomy lose more weight than can be explained by dietary changes alone. They recruit several subjects for a clinical study who have had distal gastrectomy for benign gastric-outlet obstruction. Control subjects with similar baseline weights are also enrolled and instructed to follow a diet similar to the postgastrectomy subjects during the study period. In both groups, plasma levels of several hormones are measured serially over a 24-hour period. Levels of one of the hormones are shown in the graph below:  This profile most likely represents which of the following hormones?

Quizplus · Accepted Answer

Eductional Objective: The 24-hour hormone levels in the control subjects show an increase prior to meals, followed by a sharp drop postprandially. Subjects who have had a gastrectomy, on the other hand, have lower baseline levels with less meal-related fluctuation. This pattern indicates that the hormone is likely secreted in the stomach and suppressed by food intake, which is consistent with ghrelin's secretory pattern.
Ghrelin is primarily produced in the stomach in response to fasting; levels rise before meals and fall afterward. Ghrelin promotes weight gain by stimulating appetite. Caloric restriction and decreased fat stores increase ghrelin levels (along with decreased leptin and insulin levels), limiting weight loss from dietary changes alone. Patients who have had bariatric procedures that remove a portion of the stomach (for example, roux-en-Y gastric bypass or sleeve gastrectomy) may lose a significant number of ghrelin-secreting cells. This results in lower ghrelin levels and less appetite stimulation in response to fasting, promoting weight loss.

A Group of Researchers Is Looking into Why People Who