No abstract available.
alpha-MSH* ; Obesity

BACKGROUND: There are many growth media for cultivation of human melanocytes (MGM), depending on the supplements added, and the growth of cells is closely related to these components. To understand melanocytes in vivo, it is necessary to find out the biological or biochemical characteristics of melanocytes grown in physiologic growth medium (P-MGM) and phorbol-12-myristate 13-acetate (PMA)-containing medium (C-MGM). OBJECTIVE: To investigate the expression of different biochemical markers of melanocytes grown in C-MGM and in P-MGM. METHODS: C-MGM is basically composed of PMA (10 ng/ml), and bFGF (3 ng/ml), and is now commercially available for melanocyte culture. P-MGM is a physiologic growth medium containing physiologic mitogens such as bFGF (10 ng/ml), ET-1 (10 nM), and alpha-MSH (12 nM). The cell proliferation and the expression of biochemical markers were measured in cultured human melanocytes which were grown in either C-MGM or P-MGM. RESULTS: In this study, there was significant difference in cell proliferation between cells grown in C-MGM and P-MGM (p<0.01). The tyrosinase activity and melanin contents were significantly increased in C-MGM. The expression of TRP1, MART-1 and p53 in mRNA level was higher in C-MGM than in P-MGM. The up-regulation of p53 protein expression was also observed in C-MGM. CONCLUSION: The proliferation and expression of p53, at both transcriptional and translational levels were increased when melanocytes were grown in C-MGM, compared to P-MGM. This data suggests that p53-mediated melanization is to some degree related with phorbol ester, and should further be elucidated.
alpha-MSH ; Biomarkers ; Cell Proliferation ; Humans* ; Melanins ; Melanocytes* ; Mitogens ; Monophenol Monooxygenase ; RNA, Messenger ; Up-Regulation

BACKGROUND: The effects of melanocyte stimulating hormone(MSH) on the integument of many species, including mammals, are well known. The significance of MSH as a physiological regulator of cutaneous pigmentation in humans is still controversial. Although the administration of MSH results in skin darkening, previous reports suggest that cultured human melanocytes are relatively unresponsive to this peptide. This may be related to the conditions under which the melanocytes were cultured. OBJECTIVE: The purpose of this study was to investigate the effect of alpha-MSH on the morphological changes, survival, and melanization of cultured human melanocytes in a basal medium without any mitogen. METHOD: We examined the morphological changes, number and melanin contents of cultured human melanocytes in control(absence of alpha-MSH) and experimental groups(presence of 10(-8) M, 10(-7) M, and 10(-6) M alpha-MSH). RESULTS: 1. There were no significant morphological changes of cells between the control and experimental groups after 24, 48, and 72 hours' culture. The number and length of melanocyte dendrites showed no significant difference between the groups after 24, 48, and 72 hours' culture. 2. The number of melanocytes in the experimental groups(presence of 10(-7) M, and 10(-6) M alpha-MSH) were significantly higher than the number of melanocytes in control group after 72 hours culture(p<0.05). This effect of alpha-MSH was dose-related. 3. The melanin contents slightly increased in the experimental groups. The significant difference between the groups was showed in the presence of 10(-8) M alpha-MSH. CONCLUSIONS: alpha-MSH has no effect on the morphology, but increases the survival of cultured human melanocytes and has a melanogenic effect.
alpha-MSH* ; Dendrites ; Humans* ; Mammals ; Melanins ; Melanocyte-Stimulating Hormones ; Melanocytes* ; Pigmentation ; Skin

Some malignant melanoma cells regress spontaneously by terminal differentiation, and understanding the mechanisms of this spontaneous regression can contribute to the development of a new therapy not only for melanoma but also for other cancers. The signal transducing G protein is one component of the signaling pathways for the differentiation-inducing molecules such as alpha-melanocyte-stimulating hormone (alpha-MSH) and cAMP. To investigate the role of G proteins in the differentiation process, we analyzed the expression of various G proteins by quantitative Western blot and cAMP response in human malignant melanoma cell lines. SK-MEL-3 cells expressed the largest amount of stimulatory G protein alpha subunit (G(s) alpha) and the largest amount of inhibitory G protein alpha subunit (G(i) alpha) was expressed in Malme-3M cells among the 4 melanoma cell lines analyzed in this experiment. The SK-MEL-28 cells exhibited largest amount of alpha subunit of G(q) and the beta subunits. The cAMP formation by forskolin stimulation was largest in the Malme-3M. The amount of cAMP formation did not show any correlation with the expression of G(s) alpha nor that of G(i) alpha. The population doubling time was longest in Malme-3M cells. In this experiment, we found that the melanoma cells vary widely both in the expression of various G proteins and in cAMP production depending on the cell lines.
alpha-MSH ; Blotting, Western ; Cell Line* ; Colforsin ; GTP-Binding Protein alpha Subunits ; GTP-Binding Proteins* ; Humans* ; Melanoma*

BACKGROUND: Tumor necrosis factor a (TNF), potent proinflammatory cytokine, may be related with ischemia/reperfusion injury induced tubular cell inflammation and apoptosis. We examined TNF and its major nuclear transcriptional factor, NFkappaB activation in cultured human tubular cells in hypoxic condition and the effect of alpha-MSH, potent antiinflammatory agent, which have been reported to reduce renal I/R injury in rats. METHODS: Hypoxic culture condition was produced by oxidative pathway inhibitor (Antimycin 2 mM) and glycolytic pathway inhibitor (deoxy-D- glucose 2 mM and 10 mM) for 1 hour and re-oxygenation was performed by placing the cells in normal medium. The expression of TNF mRNA was studied by RT-PCR and NFkappaB DNA binding activity was analysed by Electomobility shift assays (EMSA) and cellular apoptosis was assessed by the terminal deoxynucleotidyl transferase-mediated dUTP biotin nick-end labelling (TUNEL) method and DNA laddering. These data were compared between the alpha-MSH and the vehicle-treated groups. RESULTS: Measured ATP level was 49% of control by luciferase-based assay kit. I/R injury caused an increase in TNF mRNA and NFkappaB activation and was accompanied by morphological evidence of apoptosis. alpha-MSH significantly reduced the degree of apoptosis, as well as TNF mRNA and NFkappaB activity (TNF/L19 mRNA ratio, vehicle/alpha-MSH: 105.15 +/- 16.5/18.75 +/- 0.85, p<0.05) (NFkappaB activity, vehicle/alpha-MSH: 5624/4803 densitometric index (DI), p<0.05). CONCLUSION: These findings suggest that alpha-MSH can decrease cellular apoptosis in hypoxic tubular cells and this protective effect of alpha-MSH may be related, in partially, with supression of TNF and NFkappaB activity.
Adenosine Triphosphate ; alpha-MSH* ; Animals ; Anoxia ; Apoptosis ; Biotin ; DNA ; Glucose ; Humans* ; Inflammation ; Ischemia* ; Rats ; RNA, Messenger ; Tumor Necrosis Factor-alpha*

BACKGROUND: Although leptin and its principal mediators, neuropeptide Y (NPY) and -melanocyte stimulating hormone (MSH) are postulated to play a pivotal role in the energy balance in experimental animals, the physiologic roles of leptin and its molecular targets are not fully identified in cases of human obesity. METHODS: The subjects consisted of 16 obese women (mean BMI 35.6 kg/m2) before and after weight loss that was induced by a 2 week-very low caloric diet (800 kcal/day) and 14 normal weight women (who had a mean BMI of 20.4 kg/m2). We evaluated the plasma and cerebrospinal fluid (CSF) leptin, NPY and alpha -MSH levels and their relationship in normal weight and obese women. Additionally, changes of these peptides during a negative energy balance (800 kcal/day) were assessed in causes of human obesity. RESULTS: Obese subjects exhibited a 6.3-fold higher plasma leptin level (21.9+/-1.2 vs 3.5+/-0.4 ng/mL, p<0.05) and a 2.8-fold higher CSF leptin level (0.29+/-0.02 vs 0.10+/-0.01 ng/mL, p<0.05) compared to control subjects. The CSF/plasma leptin ratio in normal weight subjects was 2.3-fold higher than that in obese subjects. After a weight loss in obese subjects, the plasma leptin level decreased by 40% and the CSF level decreased by 51%. The CSF/plasma leptin ratio was slightly lower than the baseline level. There was a positive linear correlation between CSF and plasma leptin level at the baseline in obese subjects (r= 0.74, p<0.05) and a positive logarithmic correlation in normal weight subjects and in obese subjects after a weight loss (r= 0.66, p<0.05). The BMI negatively correlated with the CSF/plasma leptin ratio (r=-0.86, p<0.05) in any subjects. Neither the baseline plasma levels nor the baseline CSF levels of NPY were different between the normal weight subjects and obese subjects. After a weight loss the CSF NPY level decreased significantly compared to the baseline values in obese subjects. The alpha -MSH levels in plasma and CSF did not differ significantly from controls in obese subjects at the baseline or after a weight loss. The baseline CSF leptin level neither correlated with the baseline CSF NPY level nor the baseline CSF alpha -MSH level. CONCLUSION: These results demonstrated that the efficiency of leptin delivery to the CNS is reduced in human obesity and that the CNS leptin uptake involves the combination of saturable and unsaturable mechanisms. A marked reduction in the CSF leptin levels compared to the plasma level after a weight loss in obese subjects can be a potent stimulus for the body to regain weight. In contrast to the results that were observed in experimental animals, the CSF NPY and alpha -MSH did not differ from the controls in human obesity and there was no significant correlation between the CSF leptin and CSF of these neuropeptides. This could have resulted from leptin resistance in cases of human obesity although the mechanisms for this resistance remain to be determined.
alpha-MSH ; Animals ; Cerebrospinal Fluid* ; Diet ; Female ; Humans ; Leptin* ; Neuropeptide Y ; Neuropeptides ; Obesity ; Peptides ; Plasma* ; Weight Loss*

Resveratrol is a polyphenolic compound found in various natural products such as grapes and berries and possesses anti-cancer, anti-hyperlipidemia, and anti-aging properties. Recently, it has been reported that resveratrol inhibits alpha-melanocyte-stimulating hormone signaling, viability, and migration in melanoma cells. However, these effects have not been confirmed in vivo, specifically brownish guinea pigs. To evaluate the potential of resveratrol as a regulator of melanin for hyperpigmentation therapy, the influence of resveratrol on pigmentation was investigated by ultraviolet B-induced hyperpigmentation in brownish guinea pig skin. We found that resveratrol reduced the expression of melanogenesis-related proteins tyrosinase, tyrosinase-related proteins 1 and 2, and microphthalmia-associated transcription factor in melanoma cells. Furthermore, topical application of resveratrol was demonstrated to significantly decrease hyperpigmentation on ultraviolet B-stimulated guinea pig skin in vivo. Based on our histological data, resveratrol inhibits melanin synthesis via a reduction in tyrosinase-related protein 2 among the melanogenic enzymes. This study is the first to provide evidence supporting resveratrol as a depigmentation agent, along with further clinical investigation of resveratrol in ultraviolet B-induced skin disorders such as hyperpigmentation and skin photoaging.
alpha-MSH ; Animals ; Biological Products ; Fruit ; Guinea Pigs* ; Hyperpigmentation ; Melanins* ; Melanoma ; Microphthalmia-Associated Transcription Factor ; Monophenol Monooxygenase ; Pigmentation* ; Skin* ; Vitis

Resveratrol is a polyphenolic compound found in various natural products such as grapes and berries and possesses anti-cancer, anti-hyperlipidemia, and anti-aging properties. Recently, it has been reported that resveratrol inhibits alpha-melanocyte-stimulating hormone signaling, viability, and migration in melanoma cells. However, these effects have not been confirmed in vivo, specifically brownish guinea pigs. To evaluate the potential of resveratrol as a regulator of melanin for hyperpigmentation therapy, the influence of resveratrol on pigmentation was investigated by ultraviolet B-induced hyperpigmentation in brownish guinea pig skin. We found that resveratrol reduced the expression of melanogenesis-related proteins tyrosinase, tyrosinase-related proteins 1 and 2, and microphthalmia-associated transcription factor in melanoma cells. Furthermore, topical application of resveratrol was demonstrated to significantly decrease hyperpigmentation on ultraviolet B-stimulated guinea pig skin in vivo. Based on our histological data, resveratrol inhibits melanin synthesis via a reduction in tyrosinase-related protein 2 among the melanogenic enzymes. This study is the first to provide evidence supporting resveratrol as a depigmentation agent, along with further clinical investigation of resveratrol in ultraviolet B-induced skin disorders such as hyperpigmentation and skin photoaging.
alpha-MSH ; Animals ; Biological Products ; Fruit ; Guinea Pigs* ; Hyperpigmentation ; Melanins* ; Melanoma ; Microphthalmia-Associated Transcription Factor ; Monophenol Monooxygenase ; Pigmentation* ; Skin* ; Vitis

PURPOSE: The alpha-melanocyte-stimulating hormone (alpha-MSH) has been shown to interact with various cells of the immune and inflammatory system and down-regulate either the production or the action of the pro-inflammatory cytokines. In this study, we investigated the potential of alpha-MSH on preventing pancreatic islet cell from death and dysfunction by inflammatory cytokines released from peripheral blood mononuclear cells (PBMCs) in rat. METHODS: Rat pancreatic islets were co-cultured with PBMCs, stimulated by phorbol myrstic acid and ionomycin. alpha-MSH was treated to PBMCs for 2 hours before co-culture. Viability and apoptosis of islets were observed by MTT and FACS. Inflammatory cytokines and nitric oxide (NO) were measured. Insulin release from islet co-cultured with mononuclear cells was checked for the islet function. RESULTS: In comparison to control group, viability of islets with alpha-MSH treated mononuclear cells was increased and apoptosis was reduced significantly. Inflammatory cytokines such as TNF-alpha and IL-1beta were reduced in alpha-MSH-treated group. NO production in alpha-MSH-treated group was decreased. Insulin secretory function of islet was recovered in condition of alpha-MSH treatment. CONCLUSION: This study demonstrates that alpha-MSH protects cell death and preserves the secretory function of pancreatic islet cells from the pro-inflammatory reaction of mononuclear cells, and may have the potential to improve the graft survival in clinical islet transplantation.
alpha-MSH ; Animals ; Apoptosis ; Cell Death ; Coculture Techniques ; Cytokines ; Graft Survival ; Insulin ; Ionomycin ; Islets of Langerhans Transplantation ; Islets of Langerhans* ; Nitric Oxide ; Rats ; Tumor Necrosis Factor-alpha

Anti-Inflammatory Agents ; pharmacology ; Brain ; drug effects ; metabolism ; Humans ; NF-kappa B ; metabolism ; Neurons ; drug effects ; metabolism ; Tumor Necrosis Factor-alpha ; metabolism ; alpha-MSH ; pharmacology