Cyclic AMP is one of the “second messengers” that the body uses to make genes in order to transcribe hormones. Hormones have specific functions. Cyclic AMP is activated by an enzyme called adenyl cyclase on the surface of a cell.
Glucose
When glucose is ingested, it triggers an insulin secretion in the body. Insulin is a hormone that causes glucose to be stored in various tissues including the liver, fat tissue, and skeletal muscle. A small amount of insulin is ready for secretion during glucose ingestion but the rest of the insulin is transcribed from genes that glucose indirectly activates in the body.
Mechanism
Cyclic AMP is activated by a G protein on the surface of cells, specifically on the beta cells of the pancreas. The G protein is a seven-membrane protein. The activation of adenyl cyclase causes cyclic AMP to travel to the nucleus of the cell. It binds to the receptor on the nucleus and causes transcription of genes for insulin production.
Cyclic AMP’s Other Functions
Cyclic AMP is not only the second messenger for insulin secretion for glucose absorption. It is also the second messenger for other hormones, such as glucagon, calcitonin, and thyroid-stimulating hormones.