Retinyl ester

Retinyl ester is a form of vitamin A that is stored in the liver. It is a type of ester that is formed when retinol, another form of vitamin A, is combined with fatty acids. This process is essential for the body's storage and use of vitamin A.

Function

Retinyl ester plays a crucial role in the body's vision system. It is converted into retinal, a molecule that is necessary for the conversion of light into electrical signals in the retina. This process is essential for vision, particularly in low-light conditions.

In addition to its role in vision, retinyl ester also plays a role in cell differentiation, the process by which cells become specialized in their function. This is important for the growth and development of tissues and organs in the body.

Metabolism

The metabolism of retinyl ester involves several steps. First, it is hydrolyzed into retinol in the small intestine. This process is facilitated by the enzyme pancreatic lipase. The retinol is then re-esterified in the enterocytes, the cells that line the small intestine, before being packaged into chylomicrons and released into the lymphatic system.

From the lymphatic system, the chylomicrons are transported to the liver, where the retinyl ester is stored. When needed, the retinyl ester is converted back into retinol, which can then be used by the body.

Deficiency and toxicity

A deficiency in retinyl ester can lead to night blindness, a condition in which the eyes have difficulty adapting to low light. This is because retinyl ester is necessary for the production of retinal, which is essential for vision in low-light conditions.

On the other hand, an excess of retinyl ester can lead to hypervitaminosis A, a condition characterized by nausea, dizziness, and even hair loss. This is because retinyl ester is a fat-soluble vitamin, which means that it can accumulate in the body's tissues and cause toxicity if consumed in excess.

See also

• Vitamin A
• Retinol
• Retinal
• Ester
• Cell differentiation
• Chylomicron
• Hypervitaminosis A

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