|Corticotropin-releasing Hormone||OKDB#: 314|
|Synonyms:||CORTICOTROPIN-RELEASING FACTOR, CRF| CORTICOTROPIN-RELEASING HORMONE DEFICIENCY, INCLUDED| CRH DEFICIENCY, INCLUDED|||Locus:||8q13 in Homo sapiens|
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An intact hypothalamic-pituitary-adrenal axis responds to stress in mammals. Mediation of the response takes place by secretion of cortocotropin-releasing hormone (CRH) by the paraventricular nucleus of the hypothalamus. CRH is a 41-amino acid peptide derived by enzymatic cleavage from a 191-amino acid preprohormone. Shibahara et al. (1983)cloned and sequenced the human CRH gene. Arbiser et al. (1988) assigned the gene for CRH to 8q13 by somatic cell hybrid and in situ hybridization studies. The absence of secondary hybridization strongly suggested that hypothalamic and placental CRH are transcribed from the same gene. Knapp et al. (1993) showed that the homologous gene is located on mouse chromosome 3.
NCBI Summary: Corticotropin-releasing hormone (CRH) is a 41-amino acid peptide derived from a 191-amino acid preprohormone. CRH is secreted by the paraventricular nucleus (PVN) of the hypothalamus in response to stress. Marked reduction in CRH has been observed in association with Alzheimer disease and autosomal recessive hypothalamic corticotropin dificiency has multiple and potentially fatal metabolic consequences including hypoglycemia and hepatitis. In addition to production in the hypothalamus, CRH is also synthesized in peripheral tissues, such as T lymphocytes and is highly expressed in the placenta. In the placenta CRH is a marker that determines the length of gestation and the timing of parturition and delivery. A rapid increase in circulating levels of CRH occurs at the onset of parturition, suggesting that, in addition to its metabolic functions, CRH may act as a trigger for parturition.
|General function||Ligand, Hormone|
|Ovarian function||Preantral follicle growth, Steroid metabolism, Luteolysis, Oocyte maturation|
|Comment||Restraint Stress Impairs Oocyte Developmental Potential: Role of CRH-Induced Apoptosis of Ovarian Cells. Liang B 2013 et al. This study examined the role of CRH-induced ovarian cell apoptosis in the restraint stress (RS)-induced impairment of oocyte competence. Oocyte percentages of apoptotic cumulus cells (CCs) did not differ between stressed and control mice before in vitro maturation (IVM) but became significantly higher in stressed mice after IVM without serum, growth factor and hormone. The level of Bcl2 mRNA decreased significantly in mural granulosa cells (MGCs) and ovarian homogenates after RS. Whereas ovarian estradiol, testosterone and IGF1 decreased, cortisol and progesterone increased significantly following RS. RS increased the level of CRH in serum, ovary and oocyte while enhancing the expression of CRHR1 in CCs, MGCs and thecal cells. RS down-regulated ovarian expression of glucocorticoid receptor (GR) and brain-derived neurotrophic factor. Furthermore, CRH supplementation to IVM medium impaired oocyte developmental potential while increasing apoptotic CCs, an effect that was completely overcome by addition of CRHR1 antagonist antalarmin. Results suggested that RS impaired oocyte competence by increasing CRH but not glucocorticoids. Increased CRH initiated a latent apoptotic program in CCs and oocytes during their intra-ovarian development, which was executed later during IVM to impair oocyte competence. Thus, elevated CRH interacted with increased CRHR1 on thecal cells and MGCs reducing the production of testosterone, estrogen and IGF1 while increasing the level of progesterone. The imbalance between estrogen and progesterone and the decreased availability of growth factors triggered apoptosis of MGCs and facilitated CCs expression of CRHR1, which interact with the oocyte-derived CRH later during IVM to induce CCs apoptosis and reduce oocyte competence. ///////////////////////// The Effect of CRH and Its Inhibitor, Antalarmin, on in Vitro Growth of Preantral Mouse Follicles, Early Embryo Development, and Steroidogenesis. Dinopoulou V et al. In vitro growth systems of preantral follicles allow studying the effect of various endocrine, paracrine, and autocrine factors on follicular growth and oocyte maturation. CRH is a 41-amino-acid neuropeptide responsible for endocrine, autonomic, immunological, and behavioral responses of mammals to stress and has two receptors, CRH receptor type 1 (CRH-R1) and CRH-R2. Antalarmin, a CRH-R1 antagonist, has been used to elucidate the role of CRH in stress, inflammation, and reproduction. The present study describes in vitro growth of mouse preantral follicles, early embryo development, and steroidogenesis in the presence of CRH and its antagonist antalarmin. We cultured 732 follicles in control media, 1306 in CRH 10(-7) mol/liter, and 1202 in CRH 10(-7) plus antalarmin 10(-6) mol/liter. The culture medium was assayed on alternate days for 17?estradiol, progesterone, and ?human chorionic gonadotropin. Total RNA was extracted from preantral follicles as well as early preimplantation embryos and was assessed by real-time RT-PCR for the expression of CRH-R1 and CRH-R2 mRNAs. Hormone analysis showed that the CRH group had lower levels of 17?estradiol, progesterone, and ?human chorionic gonadotropin as the culture progressed, in comparison with the other two groups. RT-PCR demonstrated the presence of CRH-R1 and CRH-R2 in all stages of preantral follicle culture. Morula/blastocyst-stage embryos expressed only CRH-R1. In conclusion, CRH has an inhibitory effect on in vitro fertilized oocytes, resulting from cultured preantral follicles at all stages of preimplantation embryo development. Furthermore, the presence of CRH in the culture medium inhibits steroidogenesis by preantral mouse follicles cultured in vitro. Corticotropin-releasing hormone inhibits in vitro oocyte maturation in mice. Kiapekou E et al. The expression of corticotropin-releasing hormone (CRH) receptor 1 messenger RNA in stages of follicle growth was examined by reverse transcriptase-polymerase chain reaction in long-term cultures of early preantral mouse follicles with and without CRH addition. Corticotropin-releasing hormone receptor 1 is present in stages of mouse follicle growth, whereas 10(-9), 10(-7), and 10(-6) mol/L CRH inhibits oocyte maturation in vitro, an effect reversed by antalarmin addition. Ghizzoni et al. (1997) found that CRH exerts a CRH- and IL-1 receptor-mediated inhibitory effect on ovarian steroidogenesis and might be actively involved in the still enigmatic processes of follicular atresia and luteolysis. Ghizzoni L, et al 1997 reported that corticotropin-releasing hormone (CRH) inhibits steroid biosynthesis by cultured human granulosa-lutein cells in a CRH and interleukin-1 receptor-mediated fashion. The effects of graded doses of ovine CRH were evaluated in the conditioned medium obtained after 24 h incubation of the cells. All CRH concentrations employed except for the lowest one caused a significant decrease of media E2 and P4 levels. The alpha-helical CRH9-41 antagonist blocked the suppressive effect of 10(-9) mol/liter CRH on both E2 and P4 secretion, while it had no effect when added to the culture media without CRH. Since interleukin (IL-1)-1 mediates certain actions of CRH on leukocytes, they examined whether the CRH effect on ovarian steroidogenesis was IL-1-mediated. Interleukin-1 receptor antagonist at 10(-7) and 10(-6) mol/liter blocked the inhibitory effects of CRH on E2 and P4 secretion, while it had no effect in the absence of CRH. In conclusion, CRH exerts a CRH- and IL-1 receptor-mediated inhibitory effect on ovarian steroidogenesis and might be actively involved in the still enigmatic processes of follicular atresia and luteolysis. Calogero AE, et al 1996 reported the effects of corticotropin-releasing hormone on ovarian estrogen production in vitro. CRH inhibited FSH-stimulated estrogen production from rat granulosa cells in a dose-dependent fashion. The maximal effect was achieved at a concentration of 10(-8) M, which suppressed estrogen production by about 30%. Low concentrations of CRH (10(-10) M), incapable of modulating maximal estrogen production in response to FSH, provoked a right-ward shift of the estrogen dose-response curve to FSH. CRH (10(-8) M) suppressed the production of tritiated water (equivalent to estrogen production) from homogenates of rat granulosa cells incubated with a half-maximal concentration of FSH. Basal estrogen production by human granulosa-luteal cells was also inhibited by CRH at a concentration of 10(-10) M. The maximal effect was achieved with a concentration of 10(-8) M, which lowered estrogen production by 25%. The CRH receptor antagonist alpha-helical CRH-(9-41) antagonized the inhibitory effect of CRH on estrogen production from rat granulosa and human granulosa-luteal cells, whereas alone it had no effect. CRH did not have any effect on the intracellular cAMP content of rat granulosa and human granulosa-luteal cells. Calogero AE, et al reported that Corticotrophin-releasing hormone inhibits insulin-like growth factor-I release from primary cultures of rat granulosa cells.|
|Expression regulated by|
|Ovarian localization||Theca, Luteal cells, Stromal cells|
|Comment||Ghizzoni et al. (1997) determined that CRH immunoreactivity was localized by immunohistochemistry in the cytoplasm of thecal cells surrounding the ovarian follicles, in luteinized cells of the stroma, and in large granulosa-derived luteinized cells of developing corpora lutea. Mastorakos G, et al 1993 reported immunoreactive corticotropin-releasing hormone and its binding sites in the rat ovary. They detected cytoplasmic immunoreactive CRH (IrCRH) in theca and stromal cells and in cells within the corpora lutea, at all phases of the estrous cycle. Using a specific radioimmunoassay, they measured IrCRH in extracts of rat ovaries (0.042-0.126 pmol/g wet tissue). The mobility of the ovarian IrCRH molecule was similar to that of rat/human CRH by reverse phase HPLC. Mastorakos G, et al 1994 reported the presence of immunoreactive corticotropin-releasing hormone in normal and polycystic human ovaries. Immunoreactivity was intense in the cytoplasm of thecal cells surrounding the ovarian follicles, in luteinized cells of the stroma, and in a subpopulation of cells within the corpora lutea. No IrCRH was present in oocytes of primordial follicles. Polycystic ovaries also had IrCRH in thecal cells; however, CRH immunostaining was less prominent or completely absent from the stroma or the sparsely present corpora lutea and was clearly detected in oocytes of primordial follicles.|
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|created:||Dec. 7, 1999, midnight||by:||
|last update:||July 29, 2013, 12:19 p.m.||by:||hsueh email:|
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