insulin : peptide hormone secreted by B cells of pancreatic islets of Langerhans; has metabolic and growth-promoting effects; stimulates glucose and amino acid uptake by most cells and stimulates protein, fat, and glycogen synthesis.
insul like growth factor I (IGF-I) : Insulin-like growth factor that mediates mitosis-stimulating effect of growth hormone on bone and possibly other tissues; also known as somatomedin C.
islet of Langerhans : cluster of pancreatic endocrine cells; distinct cell secrete insulin, glucagon, somatostatin, and pancreatic polypeptide.
postabsorptive state : period during which nutrients are not absorbed by gastrointestinal tract and energy must be by body's endogenous stores.