Protein turnover and energy expenditure in normal subjects, growth hormone deficiency, acromegaly and Cushing's syndrome

This study looks at how the body manages protein and energy in people with hormone conditions — specifically growth hormone deficiency, acromegaly (too much growth hormone), and Cushing's syndrome (too much cortisol). These conditions all change how the body builds and breaks down protein. Researchers are comparing protein use in these groups to healthy volunteers, and also checking if protein metabolism improves after surgery to remove the hormone-producing tumor. You may be eligible if: - You have been diagnosed with growth hormone deficiency, acromegaly, or Cushing's syndrome, OR - You are a healthy volunteer willing to participate You may NOT be eligible if: - You have cancer - You have liver failure - You have kidney failure Talk to your doctor about whether this trial might be right for you.