HISTORY OF VITAMIN A

Ancient history:

The first sign of vitamin A deficiency is night blindness. As the vitamin A deficiency progresses, ulceration of the cornea occurs, which may lead to blindness (Blomhoff 1994). Historical research has shown that treatment of night blindness or blindness with ingestion of animal liver, which contain large amounts of vitamin A, has been practised from as early as 3500 years ago. The ancient Egyptians (2000-1500 B.C.), the ancient Greeks (Hippocrates, ca. 400 B.C.), and the Assyrians (ca. 700 B.C.) practised this, and it is also found in Chinese medicine (ca. 700 A.D.) and Arabic medicine (ca. 900 A.D.) (Wolf 1996).

Modern history:

McCollum et al.:
A fat-soluble compound isolated from butter, egg and cod liver oil (Norwegian ‘tran’) was necessary for normal growth of rats: ‘fat-soluble A’ = vitamin A

Steenbock et a.:
A compound from yellow vegetables has similar effects as ‘fat-soluble A’

Discovery of the connection of vitamin A with growth, normal tissue differentiation, and resistance against infections. The connection between vitamin A deficiency and xerophthalmia was also discovered.

Karrer et al.:
The structure of all-trans retinol is found.

Retinoic acid (RA) is discovered. This compound facilitated growth of vitamin A-deficient animals.

The connection between vitamin E and vision is discovered.

Transport protein for vitamin A in plasma is found: Retinol Binding Protein (RBP)

Intracellular transport proteins for vitamin A are found: CRBP and CRABP

Evans and Chambon:
The nuclear retinoic acid receptor (RAR) is cloned.

Mangelsdorf:
The nuclear retinoid X receptor (RXR) is cloned.

Balmer and Blomhoff:
Regulation of gene expression by the RAR/RXR heterodimer, activated by RA.

Later:
More than 500 genes are shown to be regulated by vitamin A, either directly or indirectly. These genes encode proteins involved in embryogenesis, differentiation, skin physiolgoy (keratins), immune system etc.