Cystine Supplementation Research Articles

Liver coenzyme a levels in the vitamin B 6-deficient rat

Liver CoA concentration in the rat was decreased 50% by vitamin B 6 deficiency and 66% by pantothenic acid deficiency. The decrease caused by vitamin B 6 deficiency was independent of food intake and was not remedied by cystine supplementation of a 20% casein diet.

Sulfur amino acid requirement for lactation in the rat.

SummaryA short-term lactation test has been used to study the effects of cystine supplementation for purified diets containing casein as sole protein source. Supplementation of 12, 18, and 24% casein diets with 0.5% L-cystine markedly improved lactation performance as judged by weaning weights of young and mother. Cystine supplementation of 30% casein diet improved weaning weights of young significantly with less beneficial effects on maternal weight. The data indicate that total sulfur amino acid requirement for optimal lactation in the Long-Evans rat may be placed at slightly more than 1% of the diet and that cystine may furnish at least half of this requirement.

Methionine supplements in chicken diets. III. The biochemical difference in sulphur-amino acid metabolism between White Leghorns and Australorps

The ability of White Leghorn and Australorp chickens to use supplements of methionine or cystine for growth has been studied. While chickens of both breeds responded to a cystine supplement, White Leghorns showed an increase in growth rate when methionine was added to the basal diet but Australorps showed a growth depression. The effect of intraperitoneal injection of DL-methionine on the liver cysteine content of chickens of both breeds was also studied. Injections of 10 or 20 mg DLmethionine produced significant (P < 0.05) and highly significant (P < 0.01) rises in the liver cysteine contents of White Leghorn chickens, but produced only small, non-significant rises in the liver cysteine contents of Australorp chickens. Providing methionine by either intraperitoneal injection or crop drenching did not alter the breed difference in response of liver cysteine content. This indicates no difference between breeds in ability to absorb methionine from the alimentary canal. When all data on the effect of an Injection of 20 mg DL-methionine were examined, there was a significant breed x methionine interaction. These results are interpreted as due to a blockage in the synthesis of cysteine from methionine in Australorps. Attention is drawn to the linkage of the gene (or genes) limiting this process in Australorps with a gene producing slow feathering and thus possibly conserving cysteine. Possible advantages of this linkage are discussed, and a model derived to show that genetic drift would be unlikely to separate the possible genotypes containing the balanced alleles of these genes provided the disadvantage of the unbalanced genotypes was sufficiently great.

An evaluation of the influence of DL-methionine treatment on the serum lipids of adult American males.

STUDIES with monkeys have revealed that hypercholesterolemia and subsequent vascular lesions are produced in this primate species if the animals are given a diet deficient in the sulfur-containing amino acids cystine and methionine and at the same time receive large amounts of cholesterol in the diet.1 Also in this species, as well as in rats and mice, either dietary supplements of cystine or methionine or protein rich in these amino acids will largely prevent the anticipated hypercholesterolemia and will reverse the existing abnormality produced by such procedures.2 The data of dietary surveys done by two groups of workers indicate that . . .

Effect of Untreated Corn and Mexican Tortilla Upon the Growth of Rats on a Niacin-Tryptophan Deficient Diet

A study was made of the effect of corn and Mexican tortilla upon the growth of weanling rats fed diets low in niacin and tryptophan, with and without supplements of cystine. Corn inhibited growth in cystine-supplemented rations, but tortilla actually stimulated growth. In the absence of cystine corn apparently failed to depress the growth, which was similar to that in rats fed tortilla.

Alopecia in Rats Fed Certain Soybean Oil Meal Rations.

SummaryRats fed certain soybean oil meal rations developed a characteristic hair loss which was prevented by supplementation of inositol and/or biotin. The condition did not develop if the rations contained added cystine or methionine. Inositol supplementation resulted in no marked changes in rate of growth. However, supplements of cystine and methionine markedly increased the rate of growth when added to the raw soybean oil meal basal ration. Biotin supplements had a slight stimulatory effect on growth when added to the same ration. It is believed that soybean oil meal in some manner increases the dietary requirement for biotin and/or inositol. Possible mechanisms for such action may be an alteration of the intestinal flora, some absorptive disturbance, a vitamin imbalance or the presence of antivitamins in the soybean oil meal.We are indebted to Merck and Co., Rahway, N.J., for synthetic vitamins; and to Abbott Laboratories, North Chicago, Ill., for halibut liver oil.

Choline Metabolism: VIII. The Relation of Cystine and of Methionine to the Requirement of Choline in Young Rats

Supplementary cystine (0.1 to 0.2%) or methionine improves the growth and efficiency of utilization of food in young rats on an 18% casein diet. The deposition of liver fat and the incidence of renal hemorrhagic degeneration in young rats on a low choline diet are increased by supplements of cystine (0.1 to 0.2%) which improve the nutritive value of the diet. Larger supplements of cystine have no effect on the requirement of choline. In the absence of dietary choline, 30% of casein is required to supply sufficient methionine and cystine for the prevention of signs of choline and cystine deficiency. Evidence is presented for the conclusion that methionine which is needed and used as a source of labile methyl is not utilizable as a source of cystine sulphur.

Inhibition of Growth of Rat by Oral Administration of Methyl-cholanthrene. Effects of Dietary Cystine and Methionine Supplements.

In the present communication it is desired to report preliminary results obtained in studies of the effects of certain carcinogenic substances on sulfur metabolism. The experimental approach employed in the first series of investigations is similar to that which has resulted in the demonstration that bromobenzene,1 cholic acid,2 naphthalene,3 and iodoacetic acid4 exert an inhibiting effect on the growth of the young white rat when any one of these compounds is incorporated into a basal diet of relatively low protein content. The addition of either 1-cystine or dl-methionine to the basal diet containing either bromobenzene, cholic acid, naphthalene, or iodoacetic acid resulted in a prompt stimulation of growth, despite the continued presence of the foreign organic compound in the diet. It was suggested that these organic substances are capable of producing a specific deficiency in the sulfur-containing amino acids, probably through the requirements of the organism for organic sulfur, in the form of cystine...