Liver DNA and RNA metabolism in rats fed diets lacking methionine plus cysteine with or without restricted energy.

Ponderal parameters, soluble protein content and nucleic acid (DNA and RNA) metabolism were studied in liver of growing male Wistar rats fed with different diets: control diet (Control group) containing 10% protein (casein 9.8% plus DL-methionine 0.2%); diet 2 (Group 2) containing 10% protein, lacking Met plus Cys; and diet 3 (Group 3), containing 20% protein, lacking Met plus Cys and with 50% of energy restriction (restricted food intake by experimental design). Diets 2 and 3 were compared with the control diet to know the effects produced by the lack of Met plus Cys and the energy restriction, for an experimental period of 14 days, the animals being slaughtered on the 4th, 8th and 14th days. Food intake, body and liver weights, relative liver weight, cellular size and RNA content per organ and per mg protein decreased in groups 2 and 3, group 3 being affected more than group 2. Diet 2 produced a decrease in DNA content, due to lack of Met+Cys. Acid DNAse activity per organ diminished in group 2 on days 8 and 14, and in group 3 on the 8th day. RNA/DNA ratio diminished in group 2 and 3 due to a proportional RNA reduction with respect to the DNA content. Acid RNAse activity per organ diminished in group 2 on the 8th and 14th days, RNAse per mg of protein increased in group 3 at the end of the treatment, therefore the RNA content decreased. The content of DNA in liver is lower than RNA content in rats fed diet 2 and the opposite occurs with diet 3.

[Changes in the metabolism of muscle RNA in rats given a high protein diet]. / Modificaciones del metabolismo del RNA muscular en ratas sometidas a una dieta hiperproteica.

The effect of a high protein diet (20% casein + D,L-methionine) administered to adult Wistar rats on some aspects of muscle RNA metabolism has been studied. Body weight increased in spite of lower intake. However, gastrocnemius muscle remained unmodified, although protein content increased. Total RNA decreased in the whole muscle although RNA/DNA ratio did not change. Protein synthesis capacity diminished 81% relative to controls in spite the fact that an excessive amount of available amino acids exists. RNA loss might depend on a high catabolism, since acid RNase activity increased over control values. Therefore, it may be concluded that a high protein diet leads to a lower protein synthesis capacity through an elevated RNA breakdown.

[Changes at the liver cell level in rats subjected to protein-calorie malnutrition]. / Modificaciones a nivel celular hepático en ratas sometidas a malnutrición proteico-calórica.

The effect of a low protein-calorie diet (restricted diet) on cellular growth and on RNA metabolism in Wistar rat liver has been studied. Experimentation was carried out over 30 days and the comparisons were made against well-nourished group (10% protein, controls). Liver weight and hepatic proteins dropped significantly in malnourished rats. Both rate of DNA and number of nuclei were unchanged. However, protein/DNA and liver weight/number of nuclei ratios decreased, which led to an atrophy phenomenon. DNase specific activity however, was not modified. Liver RNA content together with RNase activity dropped in deficient rats. Protein synthesis capacity (RNA/protein) did not change. These results suggest that restricted diet leads to a lower hepatocyte size with a decreased rat of RNA turnover.

[Action of cortisol on electrocardiogram and heart metabolism in rats: influence of orchidectomy]. / Modificaciones electrocardiográficas y de metabolismo cardíaco en rata, por tratamiento con cortisol: Influencia de la orquiectomía.

The action of cortisol on electrocardiogram and cardiac parameters such as cardiac weight in absolute value and relative to the corporal weight, in dry substance, and the nitrogen content of the organ, have been studied in normal (NC) and orchidectomized rats (C). Since cortisol causes an intake reduction, pair-feeding runs were conducted in order to achieve hormone action results unbiased by the effects derived from the intake restrictions. Cortisol has not change either the cardiac weight or its nitrogen content versus controls, although their parameters were found to diminish on account of the intake restriction linked to the treatment. Cortisol treatment determined also a cardiac weight increase relative to body weight by reducing the body weight of these animals. The cardiac frequency was increased by glucocorticoid action, but the increase was produced at the expense of shortening the PR intervals which pointed to a better auriculoventricular conduction. The R wave and the T wave voltages increased and decreased respectively from the cortisol action, being both clear signs of ventricular hypertrophy. Orchidectomy did not determine significant modifications either in cardiac function or metabolism.

[Effects of cortisol, malnutrition and orchiectomy on the concentrations of proteins and nucleic acids in rat muscle]. / Efectos del cortisol, malnutrición y orquidectomía en la concentración de proteinas y ácidos nucleicos en músculo de rata.

The cortisol action on some gastrocnemius muscle parameters, related to protein synthesis was studied in normal and orchidectomized male rats. Since cortisol causes an intake reduction, pair-feeding runs were conducted to achieve results of the hormone action unbiased by the effects derived from the intake restriction. Administration of cortisol in doses of 0.8 mg/100 g of body weight/day to rats from weaning up to 30 days produced a significant reduction in protein synthesis, DNA, RNA and cell number in the muscle. The intake restrictions provoked by cortisol, produced a significant reduction in protein content, cell weight, RNA, velocity of protein synthesis (RNA/proteins), protein synthesis/DNA (RNA/DNA) and produced muscle atrophy. With the exception of DNA/RNA and muscle cell number, all other parameters were reduced by the orchidectomy in control rats with normal intake, and significant differences were found in ad libitum fed and pair-fed rats. Cortisol treatment, the cortisol-provoked intake restriction and orchidectomy impaired muscle protein synthesis. Muscle protein content was reduced by intake restriction, and this effect was more pronounced by the cortisol activity, especially in orchidectomized rats, probably due to their lacking androgenic protection which would normally counteract the cathabolic action of cortisol.

[Effect of cortisol, malnutrition and orchiectomy on the concentration of proteins and nucleic acids in rat liver]. / Efectos del cortisol, malnutrición y orquidectomía en la concentración de proteínas y ácidos nucleicos en hígado de rata.

Cortisol action on some hepatic parameters related to protein synthesis has been studied in normal and orchidectomized male rats. Since cortisol causes an intake reduction, pair-feeding runs were conducted to achieve results of the hormone action unbiased by the effects derived from the intake restriction. Administration of cortisol in doses of 0.8 mg/100 g of body weight/day to rats from weaning up to 30 days produced a significant increase in DNA and cell liver numbers and a decrease in proteins/DNA, cellular weight and RNA/DNA in unorchidectomized rats. While in orchidectomized rats these parameters do not vary. The intake restriction that cortisol provokes, produced a significant reduction in protein content, proteins/DNA, cellular weight and RNA/DNA. An increase in DNA and cell numbers in unorchidectomized rats, while in orchidectomized rats produced a reduction greater in DNA and cell numbers and an increase in RNA/DNA. Orchidectomy in control rats determined a decrease in protein liver content, DNA, proteins/DNA, cell numbers and cellular weight.

[Cortisol influence on some typical parameters of protein malnutrition in rats (author's transl)]. / Influencia del cortisol sobre algunos parámetros típicos de malnutrición proteica en ratas.

A daily v.s. dose of cortisol administered to rats, induces certain metabolic modifications, which after using the "pair-fed" system have been proven to be at least partially independent of the ingesta decrease originated by cortisol. Both cortisol treatment and experimental proteic malnutrition, originate a decrease in corporal weight, a lessening of the gamma-globulins plasmatic fraction, and an elimination increase in total nitrogen, protein, creatine and creatinine in urine. Cortisol treatment determines an increase in blood red cells number, as well as an increase in total serum proteins, especially albumin, without provoking a lessening in the beta-globulins fraction, as happens in cases of proteic malnutrition.

[Effect of sodium and potassium on cardiac infarct in rats]. / Influencia del sodio y del potasio sobre el infarto cardíaco en la rata.

During the induction of myocardial infarction in the rat by isoproterenol, a decrease in the voltage of the T wave in the electrocardiogram is produced, which reflects myocardial ischemia through a previous infusion of a KCl solution; while the perfusion of NaCl increases the voltage of such wave and therefore cardiac ischemia. The values of free Pi in the myocardium increase significantly with the administration of isoproterenol. If KCl has been perfused previously, the figures of free Pi are superior in 155% of those obtained with the perfusion of NaCl. The values of all the energetic phosphates, AMP, ADP and ATP decrease inversely and in a significant way with isoproterenol and the perfusion of NaCl and KCl. The activity of creatine-phosphokinase in the myocardium decreases with isoproterenol, specially with the previous perfusion of KCl Similarly, the activity of the isoenzimes of lactic dehydrogenase L1 and L2 (alpha-HBDH), decreases, which intensifies with previous perfusion of NaCl, but diminishes with KCl. The activity of malicodehydrogenase (MDH) in the myocardium decreases with isoproterenol, even with the previous perfusion of NaCl, but in lesser degree than with KCl.

[Electrolytic and electrocardiographical correlations under 7% oxygen in nitrogen in dogs (author's transl)]. / Interrelaciones electrolíticas y electrocardiográficas bajo la acción de un 7% de O2 en N2.

Electrolytic concentrations in plasma and electrocardiographic parameters in dogs have been studied by means of lineal and canonical correlations, after the animals have been submitted to 7% oxygen in nitrogen for three hours. At the end of hypoxia there appeared hypokalemia, increased T wave potential, low R wave and enlargement of ST segment and PQ interval. The coefficients of lineal correlation between Mg++ levels in plasma and R wave potential and those of Na+ and QRS interval were reversed at the final stages of hypoxia.