Melanin (from the Greek. melas, melanos - dark, black) - amorphous pigments dark brown and black. Melanin are usually in the hair, skin, feathers and retina in vertebrates, as well as in insects and some marine invertebrates and plants. Animal physiology concentrated in special cells melanophores. Strengthening education and deposition of melanin in the skin occurs under the influence of solar and ultraviolet rays, causing the appearance of the sun and the appearance of freckles, and also under the effect of x-rays and chemical agents, as connections silver, bismuth and others, Increased content M. there is also some types of warts, cancer of the skin (melanoblastoma). M. contains carbon, nitrogen and hydrogen in the ratio of about 1 : 5 : 5, and in some cases sulphur (from 2 to 12%). Melanin is insoluble in water, acids and organic solvents, but many of them (for example, hair M.), soluble in alkalies and precipitate upon acidification solutions. This is used when receiving Meters In tissues M usually located in a complex with squirrels.
The formation of melanin in humans and animals associated with the endocrine glands. When a number of hormonal disorders (Addison's disease, chronic gipertireoidizmom, hypopituitarism, and others), as well as during pregnancy observed violations of pigmentation of the skin, hair and so on, the formation of melanin is closely connected mainly with the production of hormones by the pituitary gland (alpha - and beta-melanocytosis-moulinrouge hormones), and also with activity of the thyroid gland, with steroid and sex hormones. Cm. also Pigments.