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>In protein catabolism, one fate of the protein's nitrogen is to be converted to the polyamines, rather than to urea.
>Adding water to meat, or stressing the animals before slaughter, will increase the meat's content of the polyamines, but the longer the meat is stored, the greater will be the production of reactive oxygen products and polyamines.
>Both the liver and the muscles contain a significant amount of glycogen when they are fresh, if the animal was healthy. At first, the lack of oxygen causes the glycogen to be metabolized into lactic acid, and some fatty acids are liberated from their bound form, producing slight changes in the taste of the meat. But when the glycogen has been depleted, the anaerobic metabolism accelerates the breakdown of proteins and amino acids.
>In the absence of oxygen, no carbon dioxide is produced, and the result is that the normal disposition of ammonia from amino acids as urea is blocked, and the polyamines are formed instead. The chemical names of two of the main poly-amines are suggestive of the flavors that they impart to the aging meat: Cadaverine and putrescine. After two or three weeks of aging, there has been extensive breakdown of proteins and fats, with the production of very complex new mixtures of chemicals.
>The polyamines are increased during seizures, and they can affect the stability of the nerve cells, for example contributing to cocaine's seizure-sensitizing action. Although they tend to block free radicals, they accelerate nerve injury (Yatin, et al., 2001), and can contribute to breakdown of the blood-brain barrier (Wengenack, et al., 2000, Koenig, et al., 1989).
>The polyamines are increased in cancers, and therapies to block their formation are able to stop the growth of various cancers, including prostate, bowel, and breast cancer. Metabolites of the polyamines in the urine appear to be useful as indicators of cancer and other diseases. (In pancreatic cancer, Yamaguchi, et al., 2004; in cervical cancer, Lee, et al., 2003; in adult respiratory stress syndrome, Heffner, et al., 1995.) The quantity of polyamines in the urine of cancer patients has been reported to be 20 times higher than normal (Jiang, 1990). Polyamines in the red blood cells appear to indicate prognosis in prostate cancer (Cipolla, et al., 1990).