Melanins, production hormone

B. Excess phenylalanine inhibits tyrosinase the first step toward melanin production, thus resulting in hypopigmentation. Excess melanin leads to hyperpigmentation. Melatonin is a hormone involved in the sleep cycle. Excessive stimulation of tyrosinase would lead to more melanin and therefore hyperpigmentation. Para-hydroxyphenylpyruvate means less transamination and perhaps more tyrosine converted to melanin and hyperpigmentation. 

The differences between the groups is held to suggest that chlorpromazine increases melanin production only in certain circumstances in this study, in the presence of a high level of melanin production and when oestrogenic hormones were at high levels. The effect of chlorpromazine in increasing sensitivity to light is not, on its own, sufficient to induce melanosis (70 ). 

Hundreds of applications have been mentioned in the Zweig (1968) review acids, alkaloids, amino acids, antibiotics, antioxidants, food and feed additives, bases and amines, bile acids, carbonyls, dyes, enzymes, lipids, hydrocarbons, hormones, indoles, natural products, peptides, proteins, pesticides, plant growth regulators, pharmaceutical products, phenols, pigments (chlorophylls, xanthophylls, porphyrins, melanin, pterins, pteridines, anthocyanins, ilavonoids, etc.), polymers, purine and pyrimidine derivatives, quinones, RNA, DNA, organic sulfur compounds, steroids, sugars, toxins, vitamins, inorganic ions, and others. 

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