In the endocrine pancreas, the islets of Langerhans produce several types of hormones. The hormones include insulin, the anabolic hormone (B or beta cells); glucagon, the hyperglycemic factor (A or alpha cells); amylin, which modulates appetite (beta cells); somatostatin, the universal inhibitor of secretion (delta cells); and pancreatic polypeptide, facilitating digestion (F cells). Of these, the B (insulin-producing) cells are the most numerous.
The most common pancreatic disease requiring pharmacologic therapy is diabetes mellitus, a deficiency of insulin production or effect. Diabetes is treated with several parenteral formulations of insulin and oral or parenteral noninsulin antidiabetic agents. Glucagon, a hormone that affects the liver, cardiovascular system, and gastrointestinal tract, can be used to treat severe hypoglycemia.
Diabetes mellitus is classified into four categories: type 1, type 2, other, and gestational diabetes mellitus. Here, we focus on type 1 and type 2. Type 1 diabetes usually has its onset during childhood and results from autoimmune destruction of pancreatic B cells. Type 2 diabetes is a progressive disorder characterized by increasing insulin resistance and diminishing insulin secretory capacity. Latent autoimmune diabetes of adulthood (LADA) is a mild autoimmune form found in 10–15% of type 2 diabetes patients. Type 2 diabetes is frequently associated with obesity and is much more common than type 1 diabetes. Although type 2 diabetes usually has its onset in adulthood, the incidence in children and adolescents is rising dramatically, in parallel with the increase in obesity in this population.
High-Yield Terms to Learn
|Alpha-glucosidase ||An enzyme in the gastrointestinal tract that converts complex starches and oligosaccharides to monosaccharides; inhibited by acarbose and miglitol |
|Beta (B) cells in the islets of Langerhans ||Insulin-producing cells in the endocrine pancreas |
|Hypoglycemia ||Dangerously lowered serum glucose concentration; a toxic effect of high insulin concentrations and the secretagogue class of oral antidiabetic drugs |
|Lactic acidosis ||Acidemia due to excess serum lactic acid; can result from excess production or decreased metabolism of lactic acid |
|Type 1 diabetes mellitus ||A form of chronic hyperglycemia caused by immunologic destruction of pancreatic beta cells |
|Type 2 diabetes mellitus ||A form of chronic hyperglycemia initially caused by resistance to insulin; often progresses to insulin deficiency |
The clinical history and course of these 2 forms differ considerably, but treatment in both cases requires careful attention to diet, fasting and postprandial blood glucose concentrations, and serum concentrations of hemoglobin A1c, a glycosylated hemoglobin that serves as a marker of glycemia. Type 1 diabetes requires treatment with insulin. The early stages of type 2 diabetes usually can be controlled with noninsulin antidiabetic drugs. However, patients in the later stages of type 2 diabetes often require the addition of insulin to their drug regimen.
Insulin is synthesized as ...