Henry Jeffay

Origins and metabolism of the intracellular amino acid pools in rat liver and muscle

Abstract 1. 1. When [14C]amino acids were continuously administered to a rat by intravenous infusion, the specific activity of the liver and muscle intracellular free amino acid soon increased but even when the intracellular pool was maximally labeled, the specific activity was lower than the plasma specific activity. This observed intracellular dilution has been interpreted as being due to intracellular unlabeled protein breakdown. 2. 2. Protein catabolism in the normal fed rats contributed approx. 50% of the livers and 30% of the muscles intracellular amino acid pool. 3. 3. During the early stages of fasting as much as 90% of liver amino acid was derived from protein degradation, with a major fraction entering the plasma to supply amino acids for other tissues. After depletion of the labile liver protein, muscle protein breakdown has increased and supplied 65% of muscle intracellular amino acid pool, which in time maintained the plasma and tissue amino acid levels.

Neutral protease activity associated with the rat liver peroxisomal fraction

Abstract An enzyme activity acting at neutral pHs capable of degrading native cytoplasmic protein to peptide and amino acids has been demonstrated in the peroxisome fraction of rat liver. This peroxisomal fraction was characterized by its very low urate oxidase and catalase activity. The neutral activity and urate oxidase appears to be predominantly in the soluble portion of the peroxisomes. The preparation will degrade approx. 0.5% per h of the added cytoplasmic protein.

Alterations in Serum Proteins of Hibernating Hamsters.

Summary 1) Alterations in various fractions of serum proteins and hematocrits were studied in hibernating and non-hibernating hamsters. 2) During hibernation the hematocrit, serum albumin and beta-globulins increased to a significant degree. The increase in beta-globulins was too large to be accounted for on the basis of simple hemoconcentration. Since concentrations of neither alpha 1 nor alpha 2-globulin increased, the data were interpreted to mean that total circulating quantity of these globulins decreased. A marked decline in concentration of gamma-globulin occurred.

Measurement of C14 and S35 in a single sample

A liquid scintillation method is described for counting S/sup 35/ and C/ sup 14/ in a single sample of doubly-labeled protein. The S/sup 35/ method involves oxidation of the sample to magnesium sulfate, dissolving in glycerol, and diluting with a mixture of N,N-dimethylformamide-ethanol-toluene containing organic scintillators. The C/sup 14/ method involves oxidation of the sample to CO/sub 2/, trapping the gas in ethanolamine, and dilution with a methyl cellosolve-toluene solution of a scintillator. The combined method permits a rapid, convenient, and accurate means of determining C/sup 14/ and S/sup 35/ in the same sample. (C.H.)

Lipogenic activity and brown fat content of human perirenal adipose tissue

The incorporation of 3H2O and/or 14C-glycerol into lipids and the specific activities of the enzymes acetyl CoA carboxylase and lipoprotein lipase were measured in the perirenal and subcutaneous adipose tissue of human subjects. The perirenal adipose tissue of younger subjects with higher brown adipocyte content had higher rates of lipogenesis and enzyme activities per gram tissue than the corresponding subcutaneous tissue. However, in individual specimens, the perirenal/subcutaneous ratios of all but one of the above parameters failed to show a correlation with the brown adipocyte content of the perirenal adipose tissue. One parameter, namely 3H2O incorporation into fatty acids per adipocyte, did relate to the brown adipocyte content of the perirenal adipose tissue in four normal-weight patients only.

Distribution and Metabolism of Diphenylhydantoin in Oral and Nonoral Tissues of Ferrets

Tissue distribution of diphenylhydantoin and metabolites in oral and nonoral tissues of the ferret after administration of single and multiple doses revealed that prolonged administration resulted in high concentrations of unmetabolized DPH in oral mucosa, salivary glands, and gingiva. This suggests a direct role of unmetabolized DPH in the induced gingival hyperplasia.

Oral Changes in Normal and Scorbutic Guinea Pigs Injected with Ascorbic Acid-1-C 14

HE USE of various vitamins in the treatment of some oral pathologic conditions has been recognized. One of the vitamins that has long held the interest of the dental profession is ascorbic acid since scurvy and some forms of gingivitis have been known to respond to the oral administration of the vitamin. It should be borne in mind that this vitamin is used in practice in spite of the fact that our knowledge of its role in the metabolism of oral tissues is not understood. In scientific investigations to determine the function of ascorbic acid in oral tissues, it has been customary to utilize the research technics of a single basic science. However, in combining the efforts of the separate research disciplines in radiology, histology, and biochemistry, as we have attempted in our study, a novel, more comprehensive approach has been provided for the analysis of the basic mechanisms in ascorbic acid metabolism by oral tissues. In our studies utilizing normal and scorbutic guinea pigs injected intraperitoneally with radioactive ascorbic acid, radioautographid methods localized radioactive uptake in pulp, periodontal membrane, alveolar periosteum, cortical and supporting bone. By histochemical staining technics, the vitamin was identified and localized adjacent to the odontoblastic layer of the pulp, in the interlobar and interlobular connective tissue of the submaxillary gland and within the adrenals. By biochemical analysis, we were able to correlate the radioautographic and histochemical findings by identifying the same pattern of distribution of radioactivity in the tissues described. Neither radioautography, histochemical staining for ascorbic acid, nor chemical analysis revealed any ascorbic acid in the enamel or dentin. In addition, our biochemical studies revealed that these oral tissues showing specific pathology

A new model for the study of transport of [14C]-diphenylhydantoin through the gingival crevicular tissues in the rabbit

Abstract Radioactive molecules can be monitored as they pass from the confines of the gingival crevice into the crevicular tissues and subsequently into the blood of rabbit. Initial studies employed this technique to trace [14C]-diphenylhydantoin (DPH). Evidence suggests that DPH has an affinity for the crevicular tissues and that this tissue may be rate limiting in drug intake into serum. Administration of systemic non-radioactive DPH appeared to eliminate this effect. In all cases substantial amounts of [14C]-DPH were observed in crevicular tissue two hours after termination of the incubation. Levels of systemically administered DPH were not different in the crevicular tissue portion of rabbit gingiva and the entire gingiva.

Protein Synthesis, Microsomes, and Polyribosomes in Oral Tissues

The mechanism of protein synthesis was studied in rabbit oral tissue microsomes and bovine gingiva polyribosomes. The cell supernatant or the pH 5 fraction which contained the amino acid activation system and an energy source were required for amino acid incorporation. Ribonuclease and puromycin inhibited amino acid incorporation. Protein synthesis occurred at a high rate.

Lipogenesis in the Brown Adipose Tissue of the Fetal Baboon

The ultrastructural and lipogenic capacity of the white and brown adipose tissue (WAT and BAT) of 10 baboon fetuses (gestational age, 138-183 days) were studied. The axillary, interscapular and pericardiac sites had at least 50% brown fat cells while the retroorbital site contained white adipocytes only. Both WAT and BAT incorporated 3H2O and 14C-glycerol into lipids at similar high rates. The activities of enzyme acetyl CoA carboxylase and glycerokinase were higher than those reported in human BAT and comparable to these reported in rodent BAT under unstimulated conditions. It is concluded that in the fetal baboon adipose tissue is capable of considerable de novo lipogenesis and that, despite the differences in microscopic appearance, WAT and BAT have similar lipogenic potentials with respect to the parameters measured.