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SummaryThe growth and hemoglobin responses obtained in chicks receiving a purified diet supplemented with factor R were found not to be due to the preformed folic acid present in factor R.By means of chick liver, rat liver, and hog kidney incubation procedures the folic acid content of factor R was greatly increased. This indicated the presence of potential folic acid which did not stimulate the growth of S. faecalis, but which was available to the chick. The potential folic acid liberated by hog kidney enzymes was found to account for all of the responses obtained in the chick, whereas chick and rat liver enzymes were not as effective in liberating folic acid.The most probable explanation for the discrepancy in the folic acid content of factor R obtained following hog kidney and rat or chick liver incubations is that factor R is a mixture of conjugates of folic acid rather than one conjugate.The response to factor R was not affected by the presence of succinylsulfathiazole in the diet. Conjugated folic a...

SummaryA study in young rats (weanling to 7 weeks of age) has shown that: (1) Liver mitochondria from rats with induced hyperthyroidism were less efficient as energy transducers than controls, as judged by lower P/O ratios. (2) Liver mitochondria from hyperthyroid rats contained more coenzyme Q than did controls. (3) Accordingly, coenzyme Q probably is not involved as an intermediate for phosphorylation; but rather, in the hyperthyroid state is in an alternate pathway of electron transport by-passing phosphorylation. (4) Methionine, under the conditions of the study, exerted no antithyrotoxic effect in terms of coenzyme Q content or P/O ratios of liver mitochondria.

FOR the past two years investigations have been conducted in this laboratory to elucidate further the chemical composition of eggs. The principal objective has been to ascertain how the chemical composition varies with egg quality, in the hope that this knowledge eventually may be instrumental in the production of eggs of higher quality. In the earlier phases of this work (Charkey et al., 1947a, b) it was found that (a) egg-white fractions of eggs with high quality thick white ‡ have a higher solids content than do those of eggs with low quality thick white § ; (b) the solids of high quality egg-white fractions are higher in content of tryptophan than the corresponding low quality solids; and (c) in the case of the thick white fraction, higher in total nitrogen than the low quality solids. The explanation presenting itself as most likely to account for these facts was variation in the kind, . . .

SummaryFeeding cockerels depleted of Vit. B12 from the second to fourth weeks of age on a 70% sesame meal diet deficient in Vit. B12 and lysine resulted in a failure of morphological differentiation of testicular tissue accompanied by a decrease in comb growth. Supplementation with Vit. B12 and lysine produced markedly greater testicular growth and differentiation over that in the normal controls.

INTRODUCTION IN EARLIER work it was observed that vitamin B12 supplementation of deficient basal diets led to reduced blood levels of certain free amino acids. The chicks given vitamin B12, with lower blood levels of these amino acids grew faster, and made more efficient utilization of their feed than did the controls. This finding led to the provisional hypothesis that vitamin B12 enhances anabolic utilization of amino acids in the chick (Charkey et al., 1950); confirmed by Menge and Combs (1950). The present paper reports a further study in which that hypothesis has been put to more comprehensive test. EXPERIMENTAL Plan of Experiment. It was desired first of all to repeat, in essence, the earlier work in which effects had been observed on an ad libitum feeding basis. These effects had not been large, however, and it was thought that they might be increased by resampling all treatments after putting …

IN AN attempt to relate the quality of eggs to their chemical composition, eggs of high and low albumen quality were assayed comparatively for their content of certain vitamins. Procedures for the selection and handling of samples are detailed in the previous paper, as is also the uniform procedure for digestion and extraction of subsamples for microbiological assays. Nicotinic acid was determined by the method of Krehl, Strong and Elvehjem (1943), using Lactobacillus arabinosus 17-5 as the test organism. Apparent * folic acid and apparent* pyridoxine were measured with Streptococcus faecalis, by modifications, of the methods of Luckey, Briggs and Elvehjem (1944) and of Snell, Guirard and Williams (1942), respectively. In all microbiological assays folic acid added was the pure synthetic material. † Carotene was determined colorimetrically in a washed, dried petroleum ether extract of the saponified yolk samples. Vitamin A was measured colorimetrically also, following addition of the Carr-Price (1926) reagent . . .

Summary(1) The extent of biochemical alteration in experimental bowel obstruction shock was related directly and consistently to actual rectal temperatures developed, in both normothermic control rats and those made poikilothermic by chlorpromazine. (2) The value of hypothermia in protecting rats from bowel shock has been demonstrated. (3) Chlorpromazine was beneficial in shock only when its use led to enhancement of hypothermia. Its use at a higher environmental temperature facilitated development of hyperthermia, and aggravated the biochemical syndrome of bowel shock. Chlorpromazine appears to have no specific protective action against shock. (4) Possible mechanisms are discussed.

IN MANY types of experiments it is desirable to measure oxygen consumption of intact experimental animals. Often it is sufficient to observe relative rates of oxygen uptake, without elaborate precautions for the sake of correct absolute values. It is the purpose of the present report to describe a simple apparatus and procedure which combine advantages of certain earlier methods. The apparatus, shown in Figure 1, consists essentially of a large desiccator (10 inches inside diameter) as the animal chamber, gas buret with attached levelling bulb for maintaining atmospheric pressure, and means for providing water-saturated oxygen to the system. The desiccator is painted black for use with non-nocturnal animals, to aid in keeping them in a quiescent state. The procedure, with precautionary comments, is as follows: (a) A 6 inch petri dish containing 40 ml. of 20 percent potassium hydroxide solution is placed in the bottom of the open desiccator. (b) …

SummaryDietary iodinated casein led in chicks given dietary vit. B12 to higher cecal contents of vit. B12 and in chicks not given dietary vit. B12 to lower liver contents of vit. B12 than those found in respective controls. It is suggested that the ability of iodinated casein to increase the sensitivity of chicks to dietary vit. B12 is due in part to an interference with intestinal absorption of the vitamin.

SummaryVit. B-12 has been shown to reduce blood levels of non-protein nitrogen and of 7 individual amino acids from the levels found in vit. B-12 deficient chicks.Chicks given vit. B-12 grew more rapidly and utilized feed more efficiently than B-12 deficient controls, although the latter had higher blood levels of amino acids.Vit. B-12 appears to function in metabolism by enhancing utilization of circulating amino acids for building fixed tissues.

GLUTATHIONE (GSH) is widely distributed in living tissue and is maintained therein in relatively large amounts, as compared to most other soluble low molecular weight components of tissues. It appears to be primarily an intracellular substance, being present, if at all, in undetectable amounts in extracelllular fluids (Jocelyn, 1959; Long, 1961). Erythrocytes on the other hand contain, in common with cells in general, considerable amounts (Long, 1961). Owing to its thiol group GSH functions in oxidation-reduction reactions in tissues (Jocelyn, 1959; Mapson, 1959). It is capable of interaction in various ways with disulfide bridges of proteins (Jensen, 1959; Boyer et al., 1959); a function which is potentially of the utmost importance, as in mitosis (Rapkine, 1931; Mazia, 1954), and in the functioning of hormones (Ressler, 1958; Lazarow, 1954) and of thiol-dependent enyzmes (Vollmer, 1954; Boyer et al., 1959; Mapson, 1959), for instance. Ever since its isolation from yeast by Sir…