Halibut liver oil

The liver of meat animals is a rich source of vitamin A, for this organ is the body s main storage site of the vitamin. Fish liver oils, particularly halibut liver oil, are incredibly rich in the vitamin and are too potent to be consumed as foods. Typical food sources of vitamin A (in /ag retinol equivalents/100 g) are sheep and ox liver, 15,000 butter, 830 cheese, 320 eggs, 140 herring and... 

Note 2 Values with relating to vitamin D are for egg yolk and halibut liver oil, and those relating to vitamin E are for peanut oil and soybeam oil. 

These substances occur in butter, milk, green leafy vegetables, eggs, cod liver oil, halibut liver oil, carrots, tomatoes, and other vegetables and fruits. They arc important substances because they serve in the human body as a source of Vitamin A (see Chap. 30). 

VITAMIN A (Retinol, Yitaminum A) Occurs mainly in cod-fiver oil and halibut-liver oil, Jecoris aselli oleum and Jecoris hippoglossi oleum, respectively, and in small amounts in milk, butter, carrots and egg yolk. In earlier times vitamin A was extracted from cod-liver oil, nowadays it is synthesised (=nature-iden-tical vitamin A). 

Halibut Liver Oil. From the liver of the halibut, Hippoglossus hippoglossus L. It usually contains not less than 60,000 U.S.P. vitamin A units and not less than 500 U.S.P. vitamin D Units per gram. 

Morton, R. A., Stubbs A.L., (1946). Photoelectric Spectrophotometry Applied to the Analysis of Mixtures and Vitamin A Oils, Vol.Tl, pp. 348-350 Morton, R.A., Stubbs, A.L. (1947). A Re-examination of Halibut-liver Oil. Relation Between Biological Potency and Ultraviolet Absorption Due to Vitamin A, Biochem. /., Vol.41, pp. 525-529... 

Fig. 121. Thin-layer chromatogram of a halibut liver oil, viewed in UV light (254 nm) after scraping off the vitamin D zone located with the help of the reference chromatogram...

The first human case of chronic hypervitaminosis A was described by Josephs (1944). A 3-year-old boy who had been given halibut liver oil (72 mg retinol equivalents/day for 3 months) presented with an enlarged liver and spleen and abnormal skeletal development. 

If the rate of uptake of retinol from the intestine consistently exceeds the capacity of the liver to dispose of it, significant amounts of retinol, mainly in the form of retinyl palmitate, appear in the general circulation and may give rise to toxic effects. The effects of hypervitaminosis A are many and varied. They include increased intracranial pressure, severe headache, hyperirritability, vomiting, diarrhoea, bone decalcification and skin lesions. The condition can be fatal. It has in the past been caused by over-zealous administration of concentrated sources of the vitamin such as halibut liver oil. This may contain several hundred times as much vitamin A and 40 times as much vitamin D as cod liver oil. It has also occurred in people who have eaten polar bear or husky dog liver which contain massive amounts of vitamin A. 

Vitamin A is a vitamin found in certain animal fats, such as halibut liver oil or butter, and necessary for growth and vision of animals and the health of epithelial structures. Two forms of vitamin A are known, and there are several forms of yellow plant pigments, the carotenoids, from which the human body can make vitamin A to a variable extent. 

Halibut liver oil is obtained from halibut livers. It is an excellent source of vitamins A and D and is frequently used as a primary material in making these vitamin products. 

In 1931, P. Karrer, a Swiss researcher, isolated the active substance in halibut-liver oil and determined the chemical formula for vitamin A—the first vitamin to have its chemical structure determined. For this, and for his work with riboflavin, he received the Nobel Prize. However, vitamin A was not produced (by Karrer) in crystalline form from fish liver oils until 1937, and it did not become available in synthetic form (by Isler working in Switzerland) until 1947. Today, pure, inexpensive synthetic forms of vitamin A are readily available. 

This method was found to be applicable to Extract of Malt with Halibut-liver Oil. 

For the determination of vitamin A in galenicals containing cod-liver oil and halibut-liver oil see p. 667. 

Express as much oil as possible from ten capsules. Weigh out 0 5 g and determine the vitamin A as described under Halibut-liver Oil above. 

Cod and halibut liver oils are of medicinal interest because of their high content in vitamins A and D. 

The preservation of normal powers of dark adaptation is another function in which, according to some workers, more than one vitamin is concerned. Kimble and Gordon (21) foimd that most individuals in their experiments who had poor dark adaptation and a low level of vitamin A in the blood could be brought into the normal ranges for both these criteria by dosing with vitamin A. Other individuals, however, failed to show the usual response. This led to the belief that other factors must be involved in the utilization of vitamin A for the synthesis of visual purple, and both riboflavin and ascorbic acid were tried as supplements to the action of vitamin A. Several othenvise normal subjects with poor dark adaptation and low blood vitamin A were given 200,000 I.U. of vitamin A daily as halibut liver oil, but failed to respond. It is perhaps rather difficult in the... 

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