Cecil Entenman

Quantification of the ninhydrin color reaction as applied to paper chromatography

Abstract 1. 1. The conditions necessary for the quantification of the ninhydrin color reaction have been defined and applied to the paper chromatographic determination of amino acids. Reproducible, quantitative determination of micro amounts of amino acids was achieved. Satisfactory recovery of ninhydrin-reactive compounds added to urine, plasma, and liver samples indicates that substances ordinarily found in urine and tissues do not interfere with the quantification procedure. 2. 2. In addition, it is indicated that a ninhydrin spray made slightly alkaline with sodium hydroxide should be used when one assays for, or wishes to detect, taurine on chromatograms developed with acidic solvents.

Increased Urinary Excretion of Taurine and Urea by Rats after X-Irradiation

An excessive urinary excretion of taurine and urea has been observed in the rat after whole-body X-irradiation (1-3). Since taurine is one of the major end products of sulfhydryl oxidation (4-7) its excessive excretion suggests an increase in the rate of oxidation of this radical. Barron et al. (8-11) have shown sulfhydryl-containing enzymes to be especially sensitive to inactivation by X-irradiation. In addition, when given prior to irradiation, cysteine (12), glutathione (13), and cysteamine (14, 15) protect against radiation death through a mechanism not due to the redox potential of these substances (16). All these observations indicate a fundamental importance of sulfhydryl groups in radiation damage. Therefore, it appeared that a study of the excretion of the end products of sulfhydryl oxidation would be of value. In addition, since sulfhydryl groups are components of most proteins, the simultaneous investigation of the excretion of the end products of protein degradation might provide additional useful information. Excretion of the sulfur products of metabolism is confined almost entirely to the urine. Therefore, the extent of sulfhydryl oxidation can be estimated by measuring urinary taurine and sulfate, and the extent of protein degradation evaluated by determining urinary urea. This paper will present and attempt to interpret data on the urinary excretion of these compounds by the X-irradiated rat.

Determination of carbon 14 in fatty acids by direct mount technic.

Summary It is demonstrated in the present investigation that the C14 activity of a fatty acid sample can be readily determined by a direct procedure that avoids the dilution of activity and laboriousness associated with the preparation of BaCO3 mounts. The simplicity of this new procedure permits a single operator to mount as many as 50 samples in 8 hours with an error of reproducibility not in excess of 5%. By means of an empirically constructed curve, the observed activities can be converted to a BaCO3 basis.

Effect of Total-Body X-Irradiation on Relative Turnover of Nucleic Acid Phosphorus.∗:

Summary The incorporation of P32 into DNA; nuclear PNA (nPNA), and cytoplasmic PNA (cPNA) of liver was measured in rats which had been exposed to 2500r total body X-irradiation and in mice which had been exposed to 600r total body X-irradiation. It was found that the incorporation of P32 into cPNA was increased in all cases, while into DNA and nPNA it was depressed. In the Sprague-Dawley rats an increase in the weights of the liver was observed concurrent with the increase in cPNA specific activity. A possible interrelationship between protein and cPNA synthesis has been discussed.

The Effect of Multiple Exposures and Partial-Body X-Irradiation on Urinary Taurine Excretion by the Rat

The effect of multiple dosages, shielding and organectomies on the hourly and daily excretion of taurine following x irradiation was studied in the fasting rat. Data are tabulated and presented graphically. (auth)

BILE ACIDS AND LIPID METABOLISM II. ESSENTIAL ROLE OF BILE ACIDS IN BILE PHOSPHOLIPID EXCRETION

Abstract The isolated rat liver perfusion system has been used to study the release of bile phospholipid P 32 following the injection of inorganic P 32 into the perfusate. It was demonsrtated that in the absence of added bile salt very little PLP 32 was excreted into bile, but when bile salt was added to the perfusate the PLP 32 excretion increased markedly. At the start of bile salt infusion, the specific activity of the bile phospholipids was lower than that of the liver, but at later times the specific activity of bile phospholipids was greater than liver PL specific activity. It is suggested that bile acids play an essential role in the transport of phospholipid from liver to bile.

The fate of C14-labeled palmitic acid administered intravenously as a tripalmitin emulsion.

Summary 1. In order to test the extent of utilization of fat emulsions in parenteral feeding, palmitic acid labeled with C14 at its sixth carbon was injected intravenously, in the form of the triglyceride, into fasted rats. 2. From 36 to 59% of the administered C14 was expired as CO2 in 24 hours. 3. Considerable amounts of the administered fatty acids were stored in adipose tissues throughout the body. 4. The availability of intravenously administered tripalmitin for metabolic purposes is further shown by the finding that as much as 78% of the radioactive fatty acids recovered from the liver and small intestine had been incorporated into phospholipids.

Effect of incubation temperature on hepatic palmitate metabolism in rats, hamsters and ground squirrels

1. 1. Utilization of [1-14C]-palmitate of rat, hamster and ground squirrel liver slices was studied at 7, 17, 27 and 37°C incubation temperatures. 2. 2. Oxidation of palmitate was found to be a temperature-dependent process. 3. 3. In rat and hamster liver slices, the uptake and incorporation of palmitate into diglycerides was a temperature-independent process, whereas in ground squirrel liver slices, the uptake and incorporation of palmitate into diglycerides was a temperature-dependent process.

Urinary Excretion of Uric Acid and Allantoin by the X-Irradiated-Adrenalectomized Rat.∗†

Summary 1. X-irradiation of fasting rats with doses ranging between 150 and 1000 r caused an increased excretion of uric acid (75 to 206%) and allantoin (39 to 74%) during the first 24 hours. 2. Total purine excretion (sum of uric acid plus allantoin) tended to increase with increasing X-radiation dose. 3. Removal of adrenal glands reduced to a small extent the amount of total purine excreted but the magnitude of the increase due only to irradiation was the same in adrenalectomized and intact rats. 4. It is concluded that increased purine excretion following irradiation of the rat is not dependent on adrenal gland activity.

Observations on the oxidation of methionine-S35 to S35O4 and taurine-S35 in the x-irradiated rat.

Abstract The bulk of the excess taurine appearing in the urine of rats following x-irradiation does not appear to be derived from the oxidation of methionine, whereas the excess inorganic sulfate found in the urine is due to an increase in methionine oxidation or to an alteration in kidney function. An increase in methionine oxidation is more probable, since intraperitoneally injected sulfate-S35 does not appear in the urine at a more rapid rate. However, the increase in methionine oxidation does not appear to be the result of increased hepatic oxidation since oxidation of methionine by liver slices is not enhanced.