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POMC Peptides (pomc + peptide)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

Monitoring neuropeptide-specific proteases: processing of the proopiomelanocortin peptides adrenocorticotropin and , -melanocyte-stimulating hormone in the skin

EXPERIMENTAL DERMATOLOGY, Issue 10 2006
Simone König
Abstract:, The neuroendocrine precursor protein proopiomelanocortin (POMC) and its derived neuropeptides are involved in a number of important regulatory processes in the central nervous system as well as in peripheral tissues. Despite its important role in controlling the local activation of melanocortin (MC) receptors, the extracellular proteolytic processing of POMC peptides has received little attention. The mechanisms relevant for controlling the bioavailability of adrenocorticotropin and melanocyte-stimulating hormones for the corresponding MC receptors in the skin by specific peptidases such as neprilysin (neutral endopeptidase; NEP) or angiotensin-converting enzyme (ACE) have been addressed in a number of recent investigations. This review summarizes the current body of knowledge concerning the qualitative and quantitative POMC peptide processing with respect to the action and specificity of NEP and ACE and discusses relevant recent analytical methodologies. [source]

Immunoreactivity of corticotropin-releasing hormone, adrenocorticotropic hormone and , -melanocyte-stimulating hormone in alopecia areata

EXPERIMENTAL DERMATOLOGY, Issue 7 2006
Hei Sung Kim
Abstract:, Psychological factors are believed to play a role in the pathogenesis of alopecia areata (AA), a frequently encountered hair disorder. In our study, statistically significant elevation of psychological stress was felt by AA patients prior hair loss compared with control, which was strongly believed contributory to hair loss (t -test, P < 0.01). The corticotropin-releasing hormone (CRH) and proopiomelanocortin (POMC) mRNA have been identified in the basal layer of the epidermis and pilosebaceous units of the normal scalp. And with the recent discovery of melanocytes and dermal fibroblasts capable of corticosterone production, the presence of a local stress response system resembling the hypothalamic,pituitary,adrenal (HPA) axis has been suggested. The local stress response system is involved in regulation of the normal hair cycle, but its precise role in AA is unknown. The influence of a local HPA axis or rather, CRH,POMC axis in AA was investigated by analysing immunohistochemically the expression levels of CRH and POMC peptides, including the adrenocorticotropic hormone (ACTH) and , -melanocyte-stimulating hormone (, -MSH), in a number of AA lesions and normal scalp (as control). The epidermis and pilosebaceous units of normal scalp stained weakly with CRH, ACTH and , -MSH, whereas those from the affected sites of the AA group showed intense expression of the peptides (chi-square test, P < 0.01). The meaning of this enhanced expression and their role in the pathogenesis of AA should be further evaluated in future. [source]

Proopiomelanocortin Peptides Are Not Essential for Development of Ethanol-Induced Behavioral Sensitization

ALCOHOLISM, Issue 7 2009
Amanda L. Sharpe
Background:, Behavioral sensitization is a result of neuroadaptation to repeated drug administration and is hypothesized to reflect an increased susceptibility to drug abuse. Proopiomelanocortin (POMC) derived peptides including ,-endorphin and ,-melanocyte stimulating hormone have been implicated in development of behavioral sensitization and the reinforcing effects of alcohol and other drugs of abuse. This study used a genetically engineered mouse strain that is deficient for neural POMC to directly determine if any POMC peptides are necessary for the development of ethanol-induced locomotor sensitization. Methods:, Adult female mice deficient for POMC in neurons only (Pomc,/,Tg/Tg, KO) and wildtype (Pomc+/+Tg/Tg, WT) littermates were injected once daily with either saline or ethanol (i.p.) for 12 to 13 days. On ethanol test day (day 13 or 14) all mice from both treatment groups received an i.p. injection of ethanol immediately before a 15-minute analysis of locomotor activity. Blood ethanol concentration (BEC) was measured on ethanol test day immediately following the test session. Baseline locomotor activity was measured for 15 minutes after a saline injection 2 days later in both groups. Results:, There was no significant difference in BEC between genotypes (WT = 2.11 ± 0.06; KO = 2.03 ± 0.08 mg/ml). Both WT and nPOMC-deficient mice treated repeatedly with ethanol demonstrated a significant increase in locomotor activity on test day when compared to repeated saline-treated counterparts. In addition, mice of both genotypes in the repeated saline groups showed a significant locomotor stimulant response to acute ethanol injection. Conclusions:, Central POMC peptides are not required for either the acute locomotor stimulatory effect of ethanol or the development of ethanol-induced locomotor sensitization. While these peptides may modulate other ethanol-associated behaviors, they are not essential for development of behavioral sensitization. [source]

Total body exposure to ultraviolet radiation does not influence plasma levels of immunoreactive ,-endorphin in man

PHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE, Issue 6 2001
Marjolein Wintzen
Background/Aims: A growing number of reports support evidence of proopiomelanocortin (POMC)-derived peptides in human skin cells, although not consistently. Also the effect of ultraviolet radiation (UVR) on cutaneous and plasma levels of these POMC peptides has not been established unequivocally. We hypothesized that production of ,-endorphin (,E) may explain the sense of well-being many people experience when sun-bathing. The aim of the present study was to investigate whether exposure of the skin to UVR elevates plasma ,E. Method: Healthy volunteers (n=26) received a single, weighted dose of 15 J/cm2 of UVA. Several times during the hour following irradiation, plasma ,E- immunoreactivity (,E-IR) was determined by radioimmunoassay. The effect of repeated exposure wasassessed in 35 patients treated with UVB, UVA, or UVA-1. Plasma ACTH-IR was monitored in parallel. Results: Overall, plasma levels of ,E-IR and ACTH-IR showed no significant changes during the experiment, indicating that these peptides are not influenced by single or repeated exposures to UVR of different wavelengths. Conclusion: On the basis of these results, the skin does not appear to contribute significantly to the levels of circulating ,E or ACTH. These data offer no support for the hypothesis that exposure to UVR leads to an increased concentration of circulating ,E, which could contribute to the feeling of well-being that often accompanies sun-bathing. [source]