Corticotropin-releasing Hormone
- OMIM: 122560
- MGI: 88496
Corticotropin - releasing hormone (CRH ) and the corticotropin releasing factor (CRF), also known as corticotropin, is a polypeptide consisting of 41 amino acids and is produced in the paraventricular nucleus of the hypothalamus. From there it passes through the portal vessels to the anterior pituitary, where it is the cAMP -dependent protein kinase A is activated. This in turn stimulates the secretion of ACTH v. a ( Adrenokorticotropes hormone ) and activates the sympathetic nervous system.
The release of CRH is subject to a circadian rhythm (morning secretion stronger than in the evening ), impulses from the limbic system and the negative feedback by glucocorticoids formed under influence of ACTH.
The dividend is further stimulated by IL- 1β and TNF; the endogenous cortisol secretion is adapted to an inflammatory process in the body.
Effect
In addition to the basal and stress-induced secretion of adrenocorticotropic hormone ( ACTH) and other proopiomelanocortin ( POMC ) related peptides in endocrine function and the control of the hypothalamic- pituitary - adrenal axis, CRF seems also involved in many other central and peripheral processes to be. Thus, the participation in the cardiovascular system, in the inflammation, the reproductive system, pregnancy, suspected in thermoregulation, with food intake and the psyche.
Research
The CRH was first isolated in 1981 from Schafshypothalami and characterized. The CRF peptide is not identical in all species. To exist in several species of different CRF peptides which differ in their sequence more or less by the human CRF.
After 1981, consisting of 41 amino acids oCRF ( ovine ) by Vale et al. was isolated from Schafshypothalami, already followed in 1983 the sequence elucidation of identical rCRF (rat) and hCRF (human). oCRF differs in seven of the 41 amino acids from the r / hCRF. In the period following two non- mammalian CRF peptides, sauvagine and urotensin I, were discovered. Sauvagine consists of 40 amino acids and has been from the skin of the frog ( Phyllomedusa sauvagei ) isolated. Urotensin I comprises 41 amino acids and it has been found in the nervous system of the sucker fish ( Catostomus commersoni ) ( Grigoriadis et al., 2001). Both non- mammalian CRF peptides show a surprisingly high sequence homology ( about 50%) with hCRF.
In 1995 Joan Vaughan and employees a CRF -related peptide, which urocortin, found in mammalian organisms.