Lipotropic factor

One type of fatty liver that has been smdied extensively in rats is due to a deficiency of choline, which has therefore been called a lipotropic factor. The antibiotic puromycin, ethionine (a-amino-y-mercaptobu-tyric acid), carbon tetrachloride, chloroform, phosphorus, lead, and arsenic all cause fatty liver and a marked reduction in concentration of VLDL in rats. Choline will not protect the organism against these agents but appears to aid in recovery. The action of carbon tetrachloride probably involves formation of free radicals... 

The lipotropic factors exercise a marked effect on the biosynthesis of phospho-lipids and triglycerides. As has been mentioned above, they facilitate the phospho-lipid synthesis. The dietary deficiency of lipotropic factors favours the triglyceride production in the organism. 

Fatty infiltration of the liver. In this pathology, the triglyceride concentration in the liver is 10-fold superior to the norm. The accumulation of fat in the cyto-plasm of hepatic cells leads to an impaired liver function. The causes of this pathol-ogy are numerous one of these may be a deficiency in lipotropic factors and the associated therewith synthesis of excess triglycerides. 

While there are no epidemiologic data available on lipotropic factors and colon cancer in human populations, results of animal studies suggest a possible role for this class of nutrients (choline, methionine, vitamin and folate) in colon carcinogenesis (69). Table XVI lists results typical of those observed when rats are fed a diet high in fat, low in lipotropes and exposed to a colon carcinogen. 

Methionine is intimately related to lipid metabolism in the liver. Methionine deficiency is one of the causes of the fatty liver syndrome. Lack of methionine prevents the methylation of phosphatidylethanolamine to phosphatidylcholine, resulting in an ability by the liver to build and export very low density lipoprotein. The syndrome can be treated by the administration of choline, and for this reason, choline has often been referred to as the lipotropic factor. 

Choline (bilineurine) is a lipotropic factor in the metabolism of fatty acids in the liver of fish, poultry, and swine. It is a nonspecific source of biologically active... 

THERAP cat (VET) Nutritional factor. Dietary source of choline (lipotropic factor) in poultry. 

Calculation of the nutrient to calorie values of other known lipotropic factors for diets containing 20% fat indicate that the diets listed in Table I exceed 1972 NAS requirements. It has been suggested that all nutrient requirements be expressed as a function of energy intake (Crampton, 1964). However, until more data is available on the requirements of rats fed high fat diets, the NAS requirements extrapolated to 4500 kcal/kg should be used. 

Data on atherosclerosis are very scarce. Mann and Stare (1954) reported the possibility of predisposing monkeys to atherosclerosis by giving a diet such as to cause a borderline cystine deficiency. Labecki et al. (1955) found an effect on the chylomicronemia in man, with a possible effect on the cholesterol level, on administration of a mixture of the lipotropic factors choline, methionine, and inositol (see Section II, 12). The methionine dose, however, was very much lower than those given to the toxemia groups. The problem is complicated further by the Weitzel (1956) report of a pro-atherosclerotic effect of methionine (1 %) as revealed by the fat content of the aorta in old hens. The serum cholesterol level decreased, however. Choline and inositol similarly did not give an improvement of the process in these animals (see also Section I, 12). 

Experimental pyridoxine deficiency causes dental caries as well as atherosclerosis. Dental caries increase as a result of civilization and availability of refined and preserved food in general (see Scott, 1956). Wartime circumstances reduced dental caries (Toverud, 1956, 1957) as well as death from coronary sclerotic diseases and the incidence of toxemia of pregnancy. Cirrhosis of the liver has been mentioned also as a sequel of pyridoxine deficiency. The role of a deficiency of lipotropic factors such as choline, methionine, inositol, etc., in this respect has been known for a much longer time. Feeding of vitamin Bu can make the symptoms of atherosclerosis much worse (Annand, 1957). Pantothenic acid deficiency results in a lowering of the cholesterol level in man (Bean el al., 1955). 

Pangamic acid (formerly known as vitamin Bjj, 5-135) occurs mainly in cereals, legumes, seeds (sunflower and pmnpkin seeds) and yeast. Its nutritional value is debatable andno scientific evidence exists to substantiate any physiological function or biological effects. It probably acts (like choline) as a lipotropic factor, which stimulates... 

Like choline, which is part of the compounds which are commonly called lecithins, inositol is an important component of phospholipids which help to stabilize blood cholesterol and prevent its deposition on the walls of arteries. Sometimes, the administration of inositol has helped to reduce accumulations of fatty substances (lipids) in the blood and the liver. Hence, it is designated as an agent which aids in the utilization of lipids (a lipotropic factor). However, it appears that the actions of inositol are closely tied to those of such other nutrients as choline, essential fatty acids, phospholipids, niacin, and vitamin B-6 (pyri-doxine). Finally, it is noteworthy that the heart muscle contains high levels of inositol, which suggests that it has an important cardiac function. 

A substance that prevents accumulation of fat in the liver. Choline is probably the most important of the lipotropic factors. So, any substance capable of contributing methyl groups for choline synthesis is lipotropic. 

This review will concentrate on the immunoregulatory properties of certain lipotropic factors which participate in common metabolic pathways. These factors choline, methionine, folic acid and vitamin B 2 play a central role in cellular metabolism through their regulation of the transfer and utilization of one carbon moieties. Vitamin B 2 folic acid are necessary for the normal growth and proliferation of all human cells and a deficiency of these essential co-factors would be expected to affect the lymphatic systems whose function depends on cell division or cellular response upon challenge with a foreign stimulant. 

Choline has been extensively studied as a dietary factor in mammals and much is known about its function as a lipotropic factor and its bio-... 

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