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Biomedical subjects

A Fraile

Publications and source records attributed to A Fraile.

At least 55 records · Page 3Linked to original sources
PubMed1986

Influence of thyroidectomy on brain catecholamines during the postnatal period.

The influence of early thyroidectomy (Tx) on changes in dopamine (DA) and noradrenaline (NA) during the postnatal period (30, 45 and 60 days old) was studied in the diencephalon and the rest of the brain of male and female rats. Thyroidectomy interfered with the normal growth of the animals, decreased brain weight and markedly influenced the developmental pattern of both DA and NA in the diencephalon. When compared with control values, the DA concentration, in 45- and 60-day-old Tx male rats, was 29 and 43% lower, respectively, and 21 and 43% lower, respectively, in Tx females. Diencephalic NA levels in Tx rats were also lower than those observed in controls, 15% inferior in 45- and 60-day-old males; 27 and 22% lower, respectively, in females. Thyroidectomy does not significantly alter the level of either amine in the rest of the brain.

Animals↗
PubMed1985

Effect of gonadectomy on brain catecholamines during the postnatal period.

The effect produced by gonadectomy on dopamine (DA) and noradrenaline (NA) levels in the diencephalon and the rest of the brain of male and female rats during postnatal development has been studied. DA and NA metabolism or biosynthesis seems to be regulated by the ovarian hormones, directly or by means of hypophysary hormones, since both catecholamine levels rise acutely during postnatal development when ovariectomy is performed. In contrast with controls, the NA level is not stable at 45 days, but continues rising to day 60. Orchidectomy also acutely increases the level of diencephalic DA, but in contrast with females, its concentration progressively decreases, being at day 60 the same as in the controls. The reasons that cause this normalization, in the absence of testicular androgens, are unknown. In the same way, the extirpation of the testicles increases the diencephalic concentration of NA, the concentration change is similar to the control one: however, the level is higher. There is also a clear difference from the gonadectomized females, in which the diencephalic NA rises during 45-60 days. Gonadectomy does not significantly alter the level of DA or NA in the rest of the brain.

Aging↗
PubMed1985

The effects of adrenalectomy on the ontogenesis of brain: noradrenaline and dopamine content.

The effect of adrenalectomy on catecholamine content in the diencephalon and the rest of the brain of male and female rats during the post-natal period was studied. Seven days after adrenalectomy, there is no change in noradrenaline or dopamine content. However, the dopamine levels of both the diencephalon and the rest of the brain decrease with age between days 45 and 60, while noradrenaline content in the diencephalon and the rest of the brain remained unchanged. Thus adrenalectomy significantly affected the developmental pattern of brain dopamine.

Adrenalectomy↗
PubMed1984

Effects of thyroxine and 3,5,3'-triiodothyronine in brown adipose tissue of rats.

Rats of both sexes were either cold acclimated (6 +/- 1 degree C) or treated with thyroxine (T4) or 3,5,3'-triiodothyronine (T3) (500 micrograms/kg body wt daily s.c. for 3 weeks). Wet weight, total proteins, lipids and nucleic acids in the interscapular brown adipose tissue (IBAT) were measured. Values obtained with T4 treatment were similar to those obtained with T3 treatment. T3 is the main thyroidal hormone in the rat and it is formed from T4 deiodination in liver and kidney. As T4-treated rats have not received T3 directly and its IBAT has a similar composition to that of T3-treated rats, it is concluded that peripheral T4 deiodination is governed by the plasma T4 levels. Total proteins and DNA content were similar in cold-acclimated and T3- or T4-treated rats, which is interpreted as thyroidal hormones having an action at these levels.

Acclimatization↗
PubMed1982

[Spectrofluorometric determination of 5-hydroxytryptamine and 5-hydroxyindoleacetic acid in rat diencephalon (author's transl)].

A spectrofluorometric method to determine 5-HT and 5-HIAA in rat diencephalon has been developed, following the criterion of unifying the methodology in determining biogenic amines and their metabolites. Linearity in the method remains in the interval between 0.01 microgram and 0.05 microgram. Recovery is about 70% for amine and about 80% for the metabolite. Highest concentrations of 5-HT appear in one month old female animals, and are significantly higher than those found in the male population of the same age. Concentrations in two month old animals decrease, without significant differences between males and females. Values found for 5-HIAA seem not to change so significantly, although a slight decrease is observed in the elder males.

Age Factors↗
PubMed1982

Lipid metabolism in pregnancy. Perfusion of liver in pregnant rats.

Livers of pregnant or nonpregnant rats were perfused, and incorporation of 14C-acetate into lipids was studied. Total lipids were extracted from samples of perfusion medium, taken at the entrance and exit from the liver, at different time intervals, and from the liver homogenates at the end of the experiment. Time-course of the incorporation of 14C-acetate into different lipid classes from perfusion medium and liver tissue was compared for pregnant and nonpregnant rats. Radioactivity incorporation into circulant FFA and TG was higher in the control rats than in the pregnant animals. Contrariwise, there was a high incorporation of labelled fatty acids into phosphoglycerides in pregnant rats. There was an increase of unsaturated fatty acids of large carbon chain (24 : 1 and 22 : 6) in the perfusion media of pregnant liver. Moreover, the percentages of labelled fatty acids 16 : 1, 18 : 1 and 18 : 0 were higher in pregnant rats than in controls.

Acetates↗
PubMed1979

Comparative metabolism of histamine in two Amphibia anura.

The metabolism of histamine has been compared in Rana ridibunda and Discoglossus pictus, both Amphibia anura. An intralymphatic injection of 14C-histamine (5 microCi) was administered to the animals and the total radioactivity excreted in the urine was measured 24, 48, and 72 hours later. The metabolites excreted in the urine at 24 hours were analyzed by thin-layer chromatography and subsequent autoradiography. In both species approximately 60--70% of the injected dose was found in the urine by 72 hours. In Rana ridibunda two histamine metabolites were found: imidazoleacetic and methylimidazoleacetic acid. The present results suggest that the catabolism of histamine differs in the two species.

Amphibians↗
PubMed1978

[Electrophoretic pattern and activity of lactate dehydrogenase in Discoglossus pictus (Otth) and Rana ridibunda (Pallas) skeletal muscle and heart (author's transl)].

The electrophoretic isozyme patterns, total and specific activity of lactate dehydrogenase on skeletal and cardiac muscles in Discoglossus pictus and Rana ridibunda have been studied. The isozymes were separated out in polyacrylamide gels. The LDH activity bands were developed selectively. The percentage of the H subunits are significantly higher in Discoglossus than in Rana, probably becuase Rana is subjected to more severe anaerobic conditions during the hibernation time.

Animals↗
PubMed1977

[Spectrofluorometric determination of dopamine in small areas of rat brain (author's transl)].

A method for the extraction and quantification of Dopamine from small areas of rat brain has been developed. The extraction with solvents eliminates the column cromatography separations and allows the simultaneous processing of a good number of samples. Sample retrieval is quite high (70%) and very reproducible. The evaluation was made from areas with a minimal weight of 0.225 g. The quantification of Dopamine was obtained using spectrofluorometric techniques, reading the fluorescence of the trihydroxy indol derivate. The linear relation between the instrument readings and the concentration of Dopamine is from 0 to 0.5 microng/ml. The maximal concentration of Dopamine was found in the decorticated cerebral hemispheres (1.485 microng/g), the next highest values in the diencephalon (1.046 microng/), and the minimal concentration in the cerebellum (0.283 microng/g). The concentration of the whole brain was 0.701 microng/g.

Animals↗