Showing a part of the molecule of human insulin.A single insulin molecule is made up of two chains of amino acids, the A and Bchains, which are held together by di‐ sulphide bridges.Insulin is a hormone which is produced in the pancreas by cells of the Islets ofLangerhans.Its function is to regulate blood sugar levels.Insufficient production of insulin leads to an accumulation of glucose in theblood, causing diabetes mellitus.
These are the steps below, how hormones come into play
- Biosynthesis of a particular hormone in a particular tissue
- Storage and secretion of the hormone
- Transport of the hormone to the target cells
- Recognition of the hormone by an associated cell membrane or intracellular receptor protein
- Relay and amplification of the received hormonal signal via a signal transduction process: This then leads to a cellular response. The reaction of the target cells may then be recognized by the original hormone‐producing cells, leading to a down‐regulation in hormone production. This is an example of a homeostatic negative feedback loop.
- Degradation of the hormone.
Hormone cells are typically of a specialized cell type, residing within a particular endocrine gland, such as thyroid gland, ovaries, and testes. Hormones exit their cell of origin via exocytosis or another means of membrane transport.
The hierarchical model is an oversimplification of the hormonal signaling process. Cellular recipients of a particular hormonal signal may be one of several cell types that reside within a number of different tissues, as is the case for insulin, which triggers a diverse range of systemic physiological effects. Different tissue types may also respond differently to the same hormonal signal.