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J M Macarulla

Publications and source records attributed to J M Macarulla.

At least 55 records · Page 3Linked to original sources
PubMed1984

Effect of a single dose of triiodothyronine on the uptake of (methyl-14C)choline into chick liver phospholipids.

The effects of a single dose of 3,3'-5-triiodothyronine (T3) on the uptake of (methyl-14C) choline into liver phosphatidylcholine (PC) and lysophosphatidylcholine (LPC) were studied in chicks as a function of time up to 6 h after injection of the radioactive precursor. In all cases, chicks received the T3 dose intraperitoneally 5 h before injection of the labelled compound. T3 enhances the incorporation of 14C-choline into liver PC, showing a biphasic response; the main uptake occurs between 2 and 3 h after administering the precursor. A smaller but significant hormone-dependent increase in incorporation of the labelled compound is observed in the case of LPC. Lipid P associated to PC and LPC remains constant throughout the experiment, and does not vary with hormone treatment. It is suggested that T3-injection increases, either directly or through other metabolic processes, PC and LPC turnover in chick liver cells.

Animals↗
PubMed1984

Effect of a single dose of T3 on the uptake of (2-14C)-ethanolamine into chicken liver phospholipids.

The effect of a single dose of 3,3',5-triidothyronine (T3) on the (2-14C)-ethanolamine uptake into liver phosphatidylethanolamine (PE) and lysophosphatidylethanolamine (LPE) were determined in chicken over a period of 0.25 to 6 h after radioactive precursor injection. In all cases animals received the T3 dose intraperitoneally 5 h before the injection of the labeled compound. T3 enhances the incorporation of (2-14C)-ethanolamine into liver PE and LPE. The maximum uptake takes place at 0.25 h for LPE and 0.5 h for PE after the precursor administration. A great and significant hormone-dependent increase in the incorporation of labeled compound is observed in LPE. Lipid P associated to PE and LPE remains constant throughout the experiment, and does not vary with hormone treatment. It is suggested that T3-injection increases, either directly or through other metabolic processes, PE and LPE turnover in chicken liver cells.

Animals↗
PubMed1983

Membrane-surfactant interactions. The effect of Triton X-100 on sarcoplasmic reticulum vesicles.

The effect of Triton X-100 on purified sarcoplasmic reticulum vesicles has been studied by means of chemical, ultrastructural and enzymic techniques. At low detergent/membrane ratios (about 1 Triton X-100 per 60 phospholipid molecules) the only effect observed is an increase in vesicle permeability. Higher surfactant concentrations, up to a 1:1 detergent/phospholipid ratio, produce a large enhancement of ATPase activity. Membrane solubilization occurs as a critical phenomenon when the surfactant/phospholipid molar ratio reaches a value around 1.5:1, corresponding to 2 mumol Triton X-100/mg protein. At this point, the suspension turbidity drops, virtually all the protein and phospholipid is solubilized and every organized structure disappears. Simultaneously, a dramatic increase in the specific activity of the solubilized ATPase is observed. The sudden solubilization of almost all the bilayer components at a given detergent concentration is attributed to the relative simplicity of this membrane system. Solubilization takes place at the same surfactant/membrane ratio, at least between 0.5 and 4 mg membrane protein/ml. The non-solubilized residue seems to consist mainly of delipidized aggregated forms of ATPase.

Animals↗
PubMed1983

The impairment of mitochondrial function by Triton X-100. A study of mitochondrial respiration and energy-dependent swelling.

Coupled and uncoupled respiration, and energy-dependent phosphate swelling have been studied in rat liver mitochondria in the presence of various concentration of Triton X-100. Detergent concentrations up to 10(-5) M do not affect any of the processes under study. At 10(-5) M, Triton X-100 produces a slight decrease of coupled respiration and a considerable inhibition of mersalyl-induced shrinking in swollen mitochondria. Increasing the surfactant concentration to 10(-4), coupled as well as uncoupled O2 consumption is decreased, succinate-dependent phosphate swelling is inhibited and an energy-dependent phosphate swelling in the absence of valinomycin is observed. At 2 X 10(-4) M. Triton X-100, ATP- dependent phosphate swelling is abolished, and passive swelling may be induced by various ions. Higher detergent concentrations do not allow observation of any of these events. On the basis of these results, a model of membrane-detergent interaction is proposed.

Animals↗
PubMed1982

A comparative study of the effect of various detergents on the structure and function of sarcoplasmic reticulum vesicles.

The effects produced by the detergents Triton X-100, sodium dodecylsulphate and sodium cholate on sarcoplasmic reticulum vesicles have been comparatively studied. In all cases, maximal effects are found 5 min after detergent addition. Triton X-100 and SDS are approximately ten times more effective than cholate in protein and phospholipid solubilization. Both Triton X-100 and SDS maintain Ca++ accumulation in SR vesicles at detergent concentrations below 10(-3) M; higher concentrations cause a strong inhibition. On the other hand, cholate produces a gradual inhibition of Ca++ accumulation in the concentration range between 10(-4) M and 2.5 X 10(-2) M. Triton X-100 and SDS produce a gradual solubilization of the specific Ca++-ATPase activity up to a 10(-3) M detergent concentration, above which a strong inactivation occurs, while the enzyme solubilization increases with the presence of cholate in the whole concentration range under study. The different behaviour of sodium cholate, when compared to SDS or Triton X-100, is discussed in relation to the surfactant molecular structures. The possibility of membrane lysis and reassembly in the presence of some detergents is also considered.

Animals↗
PubMed1982

[Blood levels of lead and delta-aminolevulinic dehydratase activity in a Spanish population. Effect of occupational exposure and social habits].

The effect of tobacco and alcohol on the delta-amino levulinic dehydratase (ALA-D) activity and lead level in blood is studied in a population of workers with or without exposure to lead due to their work. The lead level in the blood of workers without exposure is about 15.9 +/- 1.7 micrograms/100 ml and is unaltered by sex. The ALA-D level for men and women is 289.7 +/- 15 U/100 ml and 255.9 +/- 10 U/100 ml respectively, the difference being due mainly to the smaller hematocrit for women. Without lead exposure smoking moderately does not change the ALA-D or the lead level, whereas alcoholic drink consumption increases the lead level but does not affect the ALA-D activity. When both factors concur the ALA-D activity decreases, while the lead level increases. With lead exposure, however, neither the ALA-D activity nor the lead level undergoes any change, with of without smoking and drinking, since the values have been completely altered by the exposure. A close relationship between ALA-D activity and lead level in blood has been found in each case.

Adult↗
PubMed1981

Liver glycogen metabolism in chicken. Activation prior to triiodothyronine-induced protein synthesis enhancement.

The depletion in glycogen levels, before enhancement in proteins synthesis, after a single Triiodothyronine (T3) injection has been previously shown in chickens and rats. The same injection of 4 microgram T3 into newborn chicken increases phosphorylase a activity in liver within 4 to 10 hours, showing a maximum at 6 hours. The lag time and the maximum relate well to glycogen level depletion in chicken. However, when phosphorylase is measured in the presence of AMP, the activity is not affected by the injection to T3. Liver cAMP levels are also increased 4 h after T3 injection, but the increase is lower than for the phosphorylase a. Glucose-6-Phosphatase an enzyme of the liver carbohydrate metabolism, which is known to be activated by a single T3 injection after the protein synthesis enhancement in rats, has a lag time of 14 hours, which occurs later than the depletion in glycogen levels.

Animals↗
PubMed1981

An early effect of cortisol, previous to its glycogenogenic action.

Cortisol produces a glycogenogenic effect 5 hours after intraperitoneal injection to 3 day old chicks. This effect is dependent on protein synthesis because it can be blocked by antibiotics such as actinomycin D. On the other hand, there is a previous glycogenolytic effect 45 minutes after cortisol administration which is independent of protein synthesis. Thyroid hormones produce a similar early effect as has been previously shown. However, the observed glycogenolysis after cortisol injection is not correlated with an enhancement in the liver cAMP levels.

Animals↗
PubMed1981

[Liver phospholipid metabolism in Gallus domesticus (author's transl)].

A method is described for the extraction and thin-layer chromatographic separation of phospholipids. Eight separate phospholipid fractions are easily distinguishable. Liver phospholipid metabolism in Gallus domesticus has been studied in newborn chicken (less than 24 h old). (1-14C) serine, 3-14C) serine, (2-14C) ethanolamine and (methyl-14C) choline were used as radioactive precursors. Serine is incorporated as lysophosphatidylserine, ethanolamine as phosphatidylethanolamine, and choline as L-alpha-glycerophosphorylcholine. The observed pathways for serine and ethanolamine incorporation and turnover are the same as those described for mammals; the main pathway for choline is the synthesis of phosphatidylcholine from lysophosphatidylcholine.

Animals↗
PubMed1980

Triton X-100 solubilization of mitochondrial inner and outer membranes.

Rat liver mitochondrial inner and outer membranes were subjected to the solubilizing effect of the nonionic detergent Triton X-100 under various conditions. After centrifugation, the supernatants (containing the solubilized fraction) and pellets were characterized chemically and/or ultrastructurally. The detergent seems to act by inducing a phase transition from membrane lamellae to mixed protein-lipid-detergent micelles. Different electron-microscopy patterns are shown by the inner membranes after treatment with different amounts of surfactant, whereas the corresponding images from outer membranes vary but slightly. Selective solubilization of various components is observed, especially in the case of the inner membrane. Some membrane lipids (e.g., cardiolipin) are totally solubilized at detergent concentrations when others, such as sphyngomyelin, remain in the membrane. Other inner-membrane components (flavins, cytochromes, coenzyme Q) show different solubilization patterns. This allows the selection of conditions for optimal solubilization of a given membrane component with some degree of selectivity. The influence of Triton X-100 on various mitochondrial inner-membrane activities was studied. The detergent seems to act especially through disruption of the topology of the functional complexes, although the activity of the individual enzymes appears to be preserved. Relatively simple enzyme activities, such as ATPase, are more or less solubilized according to the detergent concentration, whereas the more complex succinate-cytochrome c reductase activity practically disappears even at low Triton X-100 concentrations.

Animals↗
PubMed1980

[The effect of the thyroid hormone triiodothyronine on the incorporation of 32P into brain phospholipids in rat and chicken (author's transl)].

The incorporation of 32P to brain phospholipids has been studied, in chicken as well as in rat. Both animal species were at different stage of brain development, although degrees of psychomotive development were identical. It is observed that the effect of triiodothyronine is more pronounced when the degree of brain myelination is smaller. The radioactive precursor is frequently incorporated to choline and ethanolamine phospholipids, and this incorporation is higher in hyperthyroid animals with a low degree of myelination. The triiodothyronine activates, in both animal species, the salvage pathway of phospholipid biosynthesis. This activation takes place 36 h before hormone action in chicken, while in rat, the most significant differences occur 36 h after hormone action.

Animals↗
PubMed1979

[Effects of T3, T4 and methyltiouracile short-term treatments on plasma and liver lipid levels in rats (author's transl)].

The effects of short-term administration of thyroid hormones (T3 and T4) and methyltiouracile (MTU) on liver and plasma lipid levels in female rats have been comparatively studied T3 increases the levels of all the studied liver lipids and decreases the plasma lipids. T4 produces smaller and even, in some cases (liver triglycerides and cholesterol esters), opposite effects. The administration of MTU produces, in general, opposite effects to T3 and T4.

Animals↗
PubMed1979

[Effect of the thyroid hormone, triiodothyronine on fatty acid chain elongation of mitochondrial phospholipids (author's transl)].

The effect of the Thyroid Hormone Triiodothyronine (T3) on composition of Fatty Acid of Mitochondrial Phospholipids is studied. In animals (Gallus domesticus var. Cornis and White Roc.) treated with an injection of T3 containing 0.04 microgram/g body weight, increase length and insaturation increases of the hydrocarbon chains of fatty acids in mitochondrial phospholipids are observed in relation to the corresponding controls. This elongation is maximum at 14 hours after treatment with the hormone. Animals treated with T3 showed a higher proportion of stearic and eicosatrienoic acids than controls. This increase is accompanied by an equivalent decrease of the palmitic and oleic acids, their respective biosynthetic precursors. The highest proportion of long chain and unsatured fatty acids can be observed in phosphatidylethanolamines and phosphatidylcholines.

Animals↗
PubMed1978

Carotenoids from marigold (Tagetes erecta) petals and their esterified fatty acids.

The main carotenoid in Tagetes erecta petals is lutein, which is found either free or esterified to one or two fatty acids. Column and thin-layer chromatographic methods are described for the separation of the different lutein species, and compared to other, previously published, techniques. In addition, fatty acid distributions are given for whole marigold plants, crude carotenoid extracts and purified mono and diesterified luteins obtained from fresh petals as well as from commercial powdered petal preparations.

Carotenoids↗