The purpose of the research study is to better understand how beta-cells (cells in the pancreas that make insulin and help regulate blood sugar) respond to growth hormone in people with impaired fasting glucose or impaired glucose tolerance at the University of Missouri. The aim of the study is to advance understanding of how growth hormone affects beta-cells and risk factors for developing type 2 diabetes.

Inclusion Criteria:

• body mass index >18.5kg/m2 and <45.9kg/m2
• impaired fasting glucose >/= 100mg/dL, </= 126mg/dL or impaired glucose tolerance on 75g oral glucose tolerance test (blood glucose 140 to 199mg/dL at two-hours)

Exclusion Criteria:

• pregnant, planning to become pregnant during the study, or breastfeeding
• current diagnosis or history of type 1 or type 2 diabetes
• use of medications that can impact the study outcomes (e.g., GLP-1 receptor agonists)
• history of bariatric surgery
• known, uncontrolled hypothyroidism
• history of intracranial hypertension, including papilledema, or a condition that increases the risk of developing intracranial hypertension, such as Turner Syndrome, Prader-Willi Syndrome, or renal impairment
• current cancer or cancer that has been in remission less than 5 years
• first degree relative with type 1 diabetes
• evidence of anemia or significant end organ dysfunction (e.g., liver, kidney, heart disease)
• alcohol use disorder, use of controlled substances, or smoking >2 cigarettes per day
• greater than 3% weight loss within three months of screening or engaged in regular (>/= 3 days per week), continuous moderate- or high-intensity exercise of >/= 30 min duration
• mentally disabled persons, prisoners, and persons with inability to grant voluntary informed consent

The study population will consist of lean and obese people ages 18-59 with impaired fasting glucose or impaired glucose tolerance.

De-identified data will be available upon reasonable request

5 years after completion of the study