Galactosamine is a hexosamine derived from galactose with the molecular formula C6H13NO5. This amino sugar is a constituent of some glycoprotein hormones such as follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Precursors such as uridine diphosphate (UDP), UDP-N-acetyl-D-glucosamine, or glucosamine are used to synthesize galactosamine in the human body. A derivative of this compound is N-acetyl-D-galactosamine. Galactosamine is a hepatotoxic, or liver-damaging, agent that is sometimes used in animal models of liver failure. Source: Wikipedia (en)