Biomedical subjects

L Arola

Publications and source records attributed to L Arola.

At least 73 records · Page 4Linked to original sources

PubMed1986

Distribution and kinetics of injected nickel in the pregnant rat.

Radioactive nickel (Ni) was injected intraperitoneally both carrier-free and in 4 mg/kg body weight of Ni as NiCl2 doses in control and pregnant rats on days 12 and 19 after impregnation. The time-course of disappearance of radioactivity from the tissues and blood of the rat was determined, as well as the degree of incorporation of radioactivity from the injected doses. The maximal uptake of the metal 15 min after injection corresponded to kidney uptake, followed by pancreas, blood plasma and then all other target organs studied. The presence of cold nickel resulted in higher uptake of the metal without much change in the proportion of distribution between tissues. The kinetics of disappearance was similar in all tissues and was little affected by pregnancy, with mean half-lives of about 3-5 h irrespective of doses.

Animals↗

PubMed1986

Net transfer of essential metals from mother to fetus in the second half of pregnancy in the rat.

The blood and plasma as well as fetal, placental and whole conceptus levels of copper, iron, sodium, zinc, potassium, magnesium and calcium were measured in pregnant rats and their fetuses days 11-21 after conception. Maternal blood and plasma concentrations of these metals did not really change in the period studied. In the fetus, the concentrations of iron, zinc and calcium increased, whereas for the other metals, they remained practically unchanged during fetal development. The net cumulative levels of metals in the whole conceptus increased in parallel with fetal growth for most metals, except for the zinc and calcium concentrations which increased at a higher pace, especially after day 16. It is concluded that these data could only be explained by a balanced increase in fetal drainage from the mother, which does not deeply change the homeostatic maintenance of the maternal circulating metal pools.

Animals↗

PubMed1986

Effects of a nickel load upon the concentration of plasma metabolites in pregnant rats.

The effects of an intraperitoneal nickel load upon plasma glucose, urea, amino acids, lactate and glucagon, as well as upon liver glycogen have been determined in 12-and 19-day pregnant rats compared with controls. Nickel induced considerable increases in both glucose and glucagon levels, delayed in 19-day pregnant rats with respect to controls, and deep and permanent decreases in glycogen and amino acids in pregnant rats. The effects of glucagon are related to the insulin resistance of pregnant rats and a relationship between nickel toxicity and the lacking capacity to recover the basal values of some parameters is suggested.

Amino Acids↗

PubMed1986

Nickel fixation by rat plasma and 21-day placental homogenates.

The effectiveness of 19-day placenta homogenates in the binding and retention of nickel was compared with that of rat plasma in a simple dialysis system. The energy of activation of both placenta and plasma were of the same range (-5 kJ/mol). The specificity of the nickel binding system was considerable, as the presence of concentrations of zinc, iron or copper five orders of magnitude larger resulted only in the loss of a maximum of 10% of the pre-bound nickel in 24 h at 20 degrees C. This strong fixation of nickel seems to be specific and is probably the same in placenta and in plasma.

Animals↗

PubMed1986

Postnatal development of amino acid metabolism enzymes in the liver and muscle of 'cafeteria' rats.

The effect of feeding a high-energy highly palatable cafeteria diet on the liver and muscle ontogenesis of serine dehydratase, alanine transaminase, glutamine synthetase and adenylate deaminase during postnatal development of the rat has been studied. The results are in agreement with the lower amino acid utilization in cafeteria rats, both adults and during postnatal development. The feeding of excess energy coupled with high-quality protein resulted in changes in the ontogenesis of the studied enzymes that coincide with the development of protein synthesis and overall pup growth even before they had direct access to this rich diet, suggesting that cafeteria feeding already affects the amino acid metabolism of the pup through the dam's milk.

AMP Deaminase↗

PubMed1986

Sodium, potassium, magnesium and calcium tissue levels in the rat during pregnancy.

The concentration of sodium, potassium, magnesium and calcium in the tissue of 12-, 19- and 21-day pregnant rats as well as in controls and in their fetuses have been measured. Practically no changes in sodium, potassium or magnesium concentrations were detected in either maternal or fetal tissues. However, an important calcium accretion in fetuses was observed in the last quarter of intrauterine development, which paralleled a noticeable decrease in calcium stores of bone and kidney, which was followed by muscle calcium loss on day 21. This huge mobilization of calcium and stability of the other metals studied have been discussed in the light of available information as to their availability in the diet and their handling by rat placenta.

Animals↗

PubMed1986

Effect of an acute injection of nickel upon essential metal homeostasis in the rat. Influence of sex and pregnancy.

The content of calcium, copper, iron, magnesium and zinc in the plasma, liver and kidney of control female and male, as well as pregnant rats on days 12 and 19 after a i.p. injection of 4 mg/kg of nickel was studied. The content of 19-day conceptuses was also measured. The injection of nickel provoked significant alterations in the essential metal homeostasis, more marked in the case of pregnant rats, with additional differences between male and female animals. In general, nickel provoked increases in metal concentrations in tissues, with diverse changes in plasma. In a number of tissues and metals, the effects lasted up to 48 hours after the single injections, long after the nickel being washed off the animal. The results suggest some sort of long-lasting nickel effect upon metal homeostasis, which is postulated not to be directly related to acute effects and which is enhanced by pregnancy.

Animals↗

PubMed1986

Essential metals in tissues and tumor of inbred C57BL/6 mice during the infective cycle of Lewis lung carcinoma.

The variation of tissue copper, zinc, iron, calcium, magnesium, potassium and sodium content of inbred C57BL/6 mice during the infective cycle of Lewis lung carcinoma have been studied. Tissue calcium, magnesium, potassium and sodium concentrations were well maintained during the infective cycle, probably because of their large dietary availability, copper, zinc and iron, however, showed a progressive decrease in their tissue concentrations. Liver zinc increased in parallel with the metastasising process. The important decrease in tissue iron observed agress with the characterized hypoferric response to infection. However, when the losses of metals were considered on a global organism basis, the loss of iron was not paralleled by an increase in tumor iron, but a global loss was observed. The hypoferric response did not deter tumor growth, as this was able to carry on its development with significantly decreasing neoplastic tissue iron content. The only metal actively concentrated by the tumoral mass was sodium.

Animals↗

PubMed1986

Unidirectionality of the water exchange between mother and 19-day fetus in the rat.

Tritiated water was injected into 19-day pregnant rats and the rate of incorporation into their fetuses was estimated. The transfer of tritiated water from mother to fetus and then to the surrounding uterus was estimated by measuring the appearance of radioactivity in an albumin-saline solution that bathed externally one conceptus freed of its surrounding uterus except for the placental attachment. There was a very significant transfer of tritium water, even before isotopic equilibration of the fetus, estimated at more than 1.5 ml/h. The reverse, the transfer of tritium from the saline solution towards the mother, resulted in only a small fraction of that figure. The results suggest the existence of unidirectional water circulation in the materno-fetal unit: maternal arterial blood----placenta----fetal circulation----amniotic fluid----amniotic membranes----endometrium----maternal venous blood.

Amniotic Fluid↗

PubMed1985

Cadmium and lead toxicity effects on zinc, copper, nickel and iron distribution in the developing chick embryo.

The teratologic effects on chicken embryos induced by the load of 100 micrograms of cadmium or lead nitrate salts injected into the yolk on day 5 of incubation as well as their effects upon zinc, copper, nickel and iron distribution were studied. Despite a significant teratologic influence of lead, cadmium administration did not induce significant effects. A week after injections, embryo lead content, but not cadmium concentration, increased; this differential action suggested an active uptake of lead by the embryo, not observed for cadmium. Both cadmium and lead affected significantly the iron, copper and zinc homeostasis in the egg. Cadmium induced these changes probably through alterations in the metallic ion transport processes towards the embryo.

Animals↗

PubMed1985

Activities of amino acid metabolizing enzymes in the stomach and small intestine of developing rats.

The activities of aspartate and alanine transaminase, serine dehydratase, arginase, glutamate dehydrogenase, adenylate deaminase and glutamine synthetase were determined in the stomach and small intestine of developing rats. Despite the common embryonic origin of the intestine and stomach, their enzymes showed quite different activity levels and patterns of development, depending on their roles. Most enzyme activities were low during late intrauterine life and after birth, attaining adult levels with the change of diet at weaning. No arginase activity was found in the stomach and no changes were detected in adenylate deaminase in the stomach or intestine throughout the period studied. Alanine transaminase, serine dehydratase and, to some extent, glutamine synthetase levels, significantly higher in late intrauterine life, decreased after birth, suggesting that the foetal stomach has a transient ability to handle amino acids.

AMP Deaminase↗

PubMed1985

Effects of an acute administration of nickel upon blood glucose compartmentation in pregnant rats.

The effects of a nickel injection i.p. to male, female virgin and 12- and 19-day pregnant rats upon plasma glucose concentration as well as blood cell free glucose content have been determined. The hyperglycaemic response to nickel of female rats was more marked than that of males, with an increase in intracellular glucose, more marked during pregnancy, which even surpassed the plasma concentration of glucose. Twelve-day pregnant rats maintained huge intracellular glucose concentrations even after the beginning of the decline in plasma levels, whereas this was not observed in 19-day pregnant rats. The possible rôle of the conceptuses in the removal of excess circulating glucose at this age is discussed.

Animals↗

PubMed1984

Arginase activity during pregnancy and lactation.

Arginase activity in liver, kidney, small intestine and stomach of pregnant and lactating rats as well as their plasma levels have been measured. Late pregnancy as well as weaning induced a parallel increase in enzyme activity that is not reflected in the circulating urea levels. The arginase activity changes have been related to known changes in feeding and nitrogen handling patterns as well as to hormonal variations.

Animals↗

PubMed1984

Effects of 24-hour starvation period on metabolic parameters of 20-day-old rats.

The effects of a 24-hour starvation period upon 20-day-old rat pups were studied both in animals kept in the presence of their starved dams and in their absence. The relative loss of body weight was more intense in the rats that received no milk, being however, severe in both groups. There was a significant maintenance of both plasma glucose levels and total amino acids, with differences in blood glucose compartmentation and a remarkable uniformity in the effects of starvation upon individual amino-acid concentrations. A significant increase in plasma urea was observed, higher in the rats kept in the presence of the dam. Ketone bodies increased with starvation but their final levels were lower than in adults. The general pattern of metabolic change observed suggests a situation, after 24-h food deprivation, similar to that of long term starvation in adults; with an active protein amino-acid catabolism but with a remarkable maintenance of circulating foodstuff levels.

Amino Acids↗

PubMed1983

Body and organ size and composition during late foetal and postnatal development of rat.

Development induced deep anatomical changes and tissue composition alterations in the rat. To determine the extent of these changes, the organ weight and size of 19 and 21 day rat foetuses and of 1, 5, 10, 20 and 30 day old Wistar rat pups have been studied and compared with adults. Different tissues showed varying rates of cell and tissue growth as well as tissue cellularity during development. Tail length is not a good index of skeletal growth. Brain growth was much slower from late intrauterine life to adulthood than most other organs. Skin weight increased more than 3-fold between days 19 and 21 of intrauterine life. Striated muscle proportion to body weight remained practically constant throughout all postnatal life studied.

Age Factors↗

PubMed1983

Distribution of amino acids and amino-acid enzymes in whole kidney and renal cortex. Effect of 24-h starvation.

The levels of activity of amino-acid enzymes (alanine-, aspartate- and tyrosine transaminases, serine dehydratase, glutamate dehydrogenase, glutamine synthetase, arginase and adenylate deaminase) in the kidney cortex and whole kidney of control and 24-h starved adult rats have been determined from crude homogenates. The individual amino-acid content of the two kidney fractions indicated has also been studied. Serine dehydratase was found mainly in the cortex, whilst glutamine synthetase presence was mainly limited to the medulla. The distribution of adenylate deaminase and glutamate dehydrogenase is remarkably uniform along the kidney. Starvation induced decreases in arginase and adenylate deaminase activities as well as a decrease in cortical serine dehydratase. Analysis of the variance of the enzyme data showed no significant overall changes with respect to distribution and starvation. The same analysis applied to aminograms indicated only significant changes when the distribution was studied on starved samples as a whole, with changes mainly in the urea cycle and some essential amino acids. The results suggested a remarkable degree of uniformity in kidney composition both with respect to amino acid and enzyme distribution. This uniformity is not markedly affected by starvation despite the important rôle of kidney in the overall amino-acid economy of the Mammal.

AMP Deaminase↗

PubMed1983

Aspartate- and tyrosine transaminase activities in the organs of the rat during its breeding cycle.

The aspartate- and tyrosine transaminase activities of liver kidney, brain, hind leg striated muscle, skin, adipose tissue, small intestine and stomach of pregnant, lactating and post-lactating rats were determined. The ratios of activities between both enzymes were uniform in the different tissues studied, with minimal values for liver and adipose tissue. The patterns and activity ratios found during the breeding cycle of the rat agreed with tyrosine transaminase being an independent entity of aspartate transaminase in liver and adipose tissue, coexisting to some degree in most other tissues and being probably only an artifact (according to recent findings in the literature) in brain, muscle and intestine. The different patterns of change found during this period in most organs suggest different hormonal regulation and help support the possibility of an independent rôle for tyrosine transaminase in them.

Adipose Tissue↗

PubMed1983

Ontogeny of amino-acid metabolism-enzymes in peripheral tissues of developing rats.

The activities of alanine, aspartate and tyrosine transaminase, adenylate deaminase, glutamate dehydrogenase and glutamine synthetase have been measured in hind leg striated muscle, lumbar adipose tissue and lumbar skin of developing rats from late foetal to weaning stage. In a general way, despite minor differences and different physiological rôles, the three peripheral tissues studied showed a concordant enzyme activity pattern with the rôles found for these enzymes in the adult. Muscle had a more constant pattern throughout development, with wider changes in skin and widest in adipose tissue. The results found agree with a marked "synthetic" mode in the tissues studied throughout all development studied. The patterns observed agree with a strict amino-acid conservation scheme during foetal life and lactation that progressively changes with weaning towards a frank degrading mode.

AMP Deaminase↗