Melanin mouse

Kokkotou, E. G., Tiitos, N. A., Mastaitis, J. W., Slieker, L., and Maratos-Flier, E. (2001) Melanin-concentrating hormone receptor is a target of leptin action in the mouse brain. Endocrinology. 142, 680-686. 

In a study of intermediate duration, dermal application of 0.5% p-cresol for 6 weeks produced permanent depigmentation of the skin and hair of mice (Shelley 1974). A caustic effect on the skin was noted in one strain of mouse, but not another. Neither o- nor m-cresol produced any color change in the mice. The author suggests that only p-cresol is active because it mimics the structure of tyrosine, the amino acid present in melanin, so that tyrosinase acts on it, liberating free radicals that damage melanocytes. NOAEL and LOAEL values were not derived from this study because the applied dose was not reported. 

Melanin Pigment Producing Mouse Colon Cancer... 

The appropriate numbers of cells (4 xlO4 per well) of a mouse melanoma cell line were cultured in 6-well tissue culture plates. After incubation, the melanin pellets were mixed with 1 N NaOH for dissolution, and the absorbance at 475 nm was measured. 

Yoon, N., Eom, T., Kim, M., and Kim, S. (2009). Inhibitory effect of phlorotaimins isolated from Ecklonia cava on mushroom tyrosinase activity and melanin formation in mouse B16F10 melanoma cells. /. Agric. Food Chem. 57,4124-4129. 

The above results together with previous findings suggest that tryptophan could also be an alternative substrate for melanin synthesis. Chen and Chavin (60) used tryptophan as a substrate for goldfish tyrosinase while the incorporation of tryptophan in the melanin of Harding Passey mouse melanoma cells was reported by other authors (67). Tryptophan in a true melanin synthesizing system, i.e. in B16-F10 melanoma cells cultured in the presence of 2mM tryptophan, increased melanin formation on the second day (4J). 

However, when Syrian (golden) hamster melanoma cells were fused with non-melanin-producing C3H mouse cells [104], and the hybrid line was isolated by the appropriate selection, no melanin production was observed in the hybrid cells, nor were tyrosinase and dopa oxidase activities detected in their extracts [104]. The parental melanoma cells had the enzymic activities and produced pigment. Nevertheless, in the hybrid cells, which possessed the expected hybrid karyotype, the lactate and malate dehydrogenase isozyme patterns were combinations of both parental types [104]. Thus, one might conclude that in the non-melanin-producing C3H parental cells there existed a specific diffusible enzyme... 

Sziits, T, Olsson, S., Lindquist, N. G., and Ullberg, S., 1978, Long-term fat of [ C]-nicotine in the mouse Retention in the bronchi, melanin-containing tissues and urinary bladder wall. Toxicology 10 207-220. 

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