The diagnosis of Cushing syndrome is often based on:

A. Cystic fibrosis (CF) patients typically lose more salt through sweat, so they need extra salt in their diet, not a restriction. Restricting salt is not recommended for CF patients.

B. Limiting fluid intake is not appropriate for CF patients, as they often require adequate hydration to help thin mucus and improve respiratory function.

C. CF patients need a high-calorie, high-fat, and high-protein diet to support their increased metabolic demands and to help with nutrient absorption, as they often have malabsorption issues. Low-fat meals are not recommended.

D. Pancreatic enzyme replacement therapy is essential for CF patients because their pancreas does not produce enough enzymes to properly digest food. These enzymes should be taken with meals and snacks to aid digestion and nutrient absorption.

A. Insulin is secreted by beta cells of the pancreas, not alpha cells. Therefore, a lack of alpha cells would not affect insulin secretion.

B. Alpha cells of the pancreas are responsible for secreting glucagon, which helps raise blood glucose levels by promoting the release of glucose from the liver. Without alpha cells, glucagon secretion would be impaired.

C. Somatostatin and gastrin are secreted by delta cells and G cells, respectively, not alpha cells. Therefore, a lack of alpha cells would not prevent the secretion of these hormones.

D. Pancreatic polypeptides are secreted by F cells in the pancreas, not alpha cells. Therefore, a lack of alpha cells would not affect the secretion of pancreatic polypeptides.