About Urea

Urea is a waste product excreted through the urinary system. It has several commercial uses as an ingredient in dish soap, tooth-whitening products, pretzels, lotion hair removers, rock salt and dye. Urea also is used to decrease pollutants in automobile exhaust gas and as a flavor additive in cigarettes. In mild concentrations, urea has a medicinal effect. Because it's toxic in high concentrations, urea requires special management techniques

Physiology

Proteins consist of chains of amino acids. When an excessive amount of proteins are consumed, they're broken down in a process called deamination. Deamination occurs primarily in the liver and produces ammonia, a waste product. Ammonia is toxic to humans, but the body neutralizes it by transforming it into urea or uric acid, which is eventually excreted as urine.

Urination

The circulatory system carries urea to the kidneys, where the nephrons of the kidneys filter urea from the blood. The kidneys combine urea with water and other waste products to form urine. Urine passes from the kidneys to the ureter, which transports it to the bladder for storage. The bladder squeezes urine out of the body through the urethra.

Agricultural Use

Urea is a key ingredient in some fertilizers in either synthetic or organic form. Nitrogen-based fertilizers result in high-yield plant growth, and urea is about 46 percent nitrogen. As the Utah State University Cooperative Extension points out, urea is a cost-effective fertilizer for agricultural purposes but has certain management requirements. To work properly, urea must be mixed throughout the soil rather than placed as topsoil.

Medicinal Uses

Even though urea and urine are excreted as waste products, these products have medicinal uses. Ureaphil, a diuretic, is made from urea. Amino-Cerv is a cervical treatment cream containing urea. Premarin is an estrogen supplement with urine extract. Panafil is a topical ointment used to treat skin ulcers and is made from urea. Urofollitropin is a fertility drug containing urine extract.

Health and Safety

Urea is an irritant to the airway, eyes and skin. Prolonged topical exposure to urea-based fertilizers may cause contact dermatitis, an inflammation of the skin. Blood may contain varying concentrations of urea. The blood urea nitrogen test assesses the concentration of nitrogen in the blood and consequently the amount of urea. High levels of urea in the blood may be due to kidney damage, diabetes or high blood pressure. Low levels of urea may indicate malnutrition, liver damage or overhydration.