The source of insulin

Insulin is a protein hormone. Insulin is secreted by the pancreatic islet β cells. In human duodenal side, there is a long-shaped organ, called the pancreas. Many scattered in the pancreas cell clusters called islets. Pancreas islet total of around 100 to 200 million. Islet cell function in accordance with their secretion of hormones into the following types: ① B cells (β cells), islet cells about 60% to 80%, insulin secretion, insulin can lower blood sugar. ② A cells (α cells), accounting for about 24% of islet cells to 40% secretion of glucagon, the role of glucagon with insulin contrary, can increase blood sugar. ③ D cells, or about 6% of the total number of islet cells to 15%, growth hormone inhibiting hormone secretion.

Diabetes, due to infection, autoimmune, genetic and other risk factors, pathophysiology activity was mainly due to the relative or absolute lack of insulin and glucagon activity due to the relative or absolute excess, ie, B and A cells Bilateral dysfunction caused by hormones. Insulin-dependent diabetes mellitus insulin-secreting cells or complete absence of serious damage, endogenous insulin secretion is very low, needed exogenous insulin therapy. Non-insulin-dependent diabetes mellitus, insulin secretion less obstacles, based on normal or elevated insulin levels, and glucose-stimulated insulin secretion are generally lower than those of the corresponding weight, that is the relative lack of insulin.

Insulin secretion mainly by the following factors:

(1) blood glucose concentration on insulin secretion of the most important factor. After oral or intravenous glucose, insulin release was two-phase reaction. Early rapid phase, portal venous plasma insulin in the 2 minutes that is the highest value, then decreased rapidly; delay of the slow phase, the plasma insulin level after 10 minutes then gradually increased and lasted for more than 1 hour. Early phase showed fast storage of glucose to promote insulin release, the delay of the slow phase shows the synthesis of insulin and insulin changes in insulin.

(2) eat more food containing protein, the blood amino acid concentration, insulin secretion increased. Arginine, lysine, leucine and phenylalanine have a strong stimulation of insulin secretion.

(3) an increase of gut after meals can stimulate insulin secretion such as gastrin, endocrine pancreas, stomach Yi Tai, vasoactive intestinal peptide are stimulated insulin secretion.

(4) free nerve function could affect insulin secretion. The excitation of the vagus nerve to promote insulin secretion; sympathetic nerve activity is inhibited when insulin secretion.