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Biomedical subjects

G Csaba

Publications and source records attributed to G Csaba.

At least 163 records · Page 9Linked to original sources
PubMed1994

Administration of benzpyrene and allylestrenol in fetal or neonatal periods of life: does it make difference in the microsomal activity?

Administration of allylestrenol or benzpyrene in fetal and neonatal periods of life make the rats susceptible to phenobarbiturate induction. Changes to controls could be observed in three of the enzyme activities tested (p-nitrophenol-hydroxylase, cytochrome P450 and aniline-hydroxylase), with a dominance of the p-nitrophenol-hydroxylase among them. There seemed to be no difference in the action of allylestrenol and benzpyrene, although treatment protocol in the neonatal period proved to be more effective.

Allylestrenol↗
PubMed1994

Changes in binding of monoclonal antibodies to TSH receptor following thyrotropin (TSH) and gonadotropin (GTH) pretreatments (studies on human thyroid and CHO cell lines).

Monoclonal antibody to TSH-receptor binds to the cells of human thyroid gland and to Chinese hamster ovary cell cultures. Pretreatments with TSH can decrease the binding of antibody, which effect is more expressed in CHO than in thyroid cells. Gonadotropin (FSH + LH) cannot influence the binding of antibody to thyroid, but there is an effect on CHO cells. Endotoxin (lipopolysaccharide, LPS) can depress the binding of antibodies on both objects and abolishes the difference between thyrotropin and gonadotropin receptors in their binding capacity, on both cell types. The experiments prove the similarity of thyrotropin and gonadotropin receptors which is responsible for the hormonal overlap.

Animals↗
PubMed1994

Effects of benzpyrene and allylestrenol administered during pregnancy on the sexual behaviour of castrated and hormone treated adult rats.

Treatments with benzpyrene on the 15th, 17th and 19th day of the pregnancy result in sexually significantly less active offspring females following castration and treatments with sexual hormones in adulthood. The receptivity of animals treated with allylestrenol in embryonic period is also decreased but was not significant. Treatments with allylestrenol or benzpyrene of newborns did not alter the hormone-induced sexual behaviour. Comparing with our previous experiments it seems that the effect of benzpyrene--which is structurally more distinct however it binds to the steroid receptor--is more pronounced on the sexual behaviour than allylestrenol.

Allylestrenol↗
PubMed1994

Effect of hormones and hormone-induced imprinting on the serotonin level in Tetrahymena: immunocytochemical studies.

Tetrahymena contains serotonin (5-HT) which it is able to take up from the environment and store. The relatives of serotonin and its basic amino acid (tryptophane, 5-hydroxytryptophane, gramine) induce a decrease of serotonin just after treatment. Subsequently (24 h), there is an increase of 5-HT which is followed by a permanent decrease in the offspring generations 1 week later. Histamine has a different effect causing an increase in serotonin immediately after treatment, which then returns to the control level after 24 h. In the daughter cells of the histamine pretreated (imprinted) cells there is an enormous increase of 5-HT at the second encounter with histamine. Thyroxine and its precursors (tyrosine, monoiodotyrosine, diiodotyrosine, triiodothyronine) are able to influence the 5-HT level, particularly diiodotyrosine, and previous experiments have demonstrated the outstanding influence of precursor molecules on the growth of Tetrahymena. The effect of non-hormone peptides and peptide hormones on the level of serotonin varies, and there are more characteristic changes in the 5-HT level with the use of hormones having known physiological effects on Tetrahymena.

Animals↗
PubMed1994

Effect of allylestrenol exposure during pregnancy on the activity of microsomal enzyme system (PSMO) of rat in the F1 and F2 generations.

Treatment of pregnant rats with allyestrenol on the 15th and 19th days of pregnancy induced the activity of enzyme system of adult offspring in females while it did not influence it in males. The steroid anticoncipient treatment of adults decreased the activity of some enzymes of the PSMO. The adulthood anticoncipient steroid treatment of rats which encountered allylestrenol in their fetal age compared to the only anticoncipient steroid treated group produces an increased activity of the majority of the tested parameters both in females and males. The effect of the adulthood alcohol treatment was not influenced by the embryonic treatment with allylestrenol. Differences in the second generation are non-significant.

Allylestrenol↗
PubMed1994

Response of liver cells to insulin at 1 week postnatal as influenced by a prior action of the same hormone at the time of birth (hormonal imprinting): an electron microscopic study.

Liver cells of rats given a single insulin dose at birth (imprinted) do not alter from the controls at 1 week postnatal. When hormone treatment occurs at 1 week postnatal without any prior administration of it, an increase in glycogen and lipid with nuclear deposition of the latter can be seen. The cell surface displays a dense layer, and increased micropinocytosis is accompanied by an increase in the number of coated pits and vesicles. Liver cells of imprinted animals treated repeatedly at 1 week postnatal have much more glycogen and lipid, and more prominent endoplasmic reticulum but a less mature Golgi apparatus. The dense substance of the cell surface is missing and the signs of endocytosis are rarely seen. These alterations indicate the influence of imprinting on hormone binding and possibly on the next steps after interaction in the cell.

Aging↗
PubMed1994

Secretory response of Tetrahymena to insulin: the influence of electric pulses.

The secretion of the enzyme hexosaminidase (HA) by Tetrahymena pyriformis, T. thermophila and T. thermophila mutant (MS1) cells was studied on the action of insulin or insulin in combination with electric pulses. The three species of Tetrahymena responded by different rates of enzyme activity. Following insulin or insulin + electrical pulses, the daughter cells of T. pyriformis manifested similar effects 24 h later by elevating the extracellular HA level, being higher when electrical pulses were included in the action on the parental cells. Insulin combined with electric pulses gave higher inter-strain differences in the reaction of Tetrahymena as reflected by HA enzyme measurements. MS1 cells lacking the capacity to release lysosomal enzymes when exposed to insulin with electric stimulation elicited a high level of HA released.

Animals↗
PubMed1994

Effect of the tyrosine kinase inhibitor tyrphostin on insulin binding and insulin imprinting of Tetrahymena.

After 10 min treatment with the tyrosine kinase inhibitor tyrphostin the fluorescein isothiocyanate (FITC)-insulin binding of Tetrahymena was increased. This binding characteristic was not changed when tyrphostin and insulin acted together. Consecutive treatments with 10 min tyrphostin and 10 min insulin further increased the FITC-insulin binding. Due to the effect of treatment with tyrphostin there was a decreased insulin binding in the offspring generations after 24 h. There was increased insulin binding in those cells of which the progenitor was treated not only by tyrphostin but also with insulin, but the insulin binding was still below the control level in this group. The increase of binding in the offspring generations of cells which were treated consecutively by tyrphostin and insulin compared with cells treated with only tyrphostin was not less than the increase of binding in the offspring of the untreated and insulin pretreated (24 h before) cells. This meant that tyrphostin had the potency to decrease insulin binding in the offspring generations but the development of imprinting was not influenced.

Animals↗
PubMed1994

Effects of hormones on chemotaxis in Tetrahymena: investigations on receptor memory.

The peptide type hormones such as insulin and adenocorticotropic hormone (ACTH) have a positive chemoattractant effect on Tetrahymena. Non-hormone protein-sulphate provoked negative chemoattraction. Of the amino acid type hormones, serotonin produced negative, and the histamine and di-iodotyrosine induced positive chemotactic effects. The first encounter with these molecules may modify the chemotactic behaviour of the progeny cells. In a significant number of cases there was a different response after repeated encounters of cells and hormones.

Adrenocorticotropic Hormone↗
PubMed1993

Presence in and effects of pineal indoleamines at very low level of phylogeny.

The unicellular organism Tetrahymena contains serotonin and is able to take up the hormone from its milieu. The serotonin content of the cell changes as a function of the presence of foreign exogenous hormones. This indicates a possible role of serotonin as a chemical mediator. Exogenous serotonin stimulates the RNA synthesis of Tetrahymena, and it was the only one among the hormones studied which kept the RNA level durably high. Serotonin stimulates phagocytosis and growth of Tetrahymena, and its precursors also stimulate growth. Serotonin can imprint Tetrahymena, and as a consequence of this the effect of the hormone increases in the case of further encounters. Treatment with serotonin-related molecules soon after imprinting can reduce the effect of imprinting. Melatonin can contract the pigment cells of Planaria; however, its precursors serotonin and tryptamine can do this more intensely. Both melatonin and serotonin can influence the regeneration of Planaria, with effects which differ when different phenomena are studied. Evolutionary theories are discussed.

Animals↗
PubMed1993

The effect of epinephrine on the intracellular free calcium of parent and Ki-ras-transfected NIH3T3 cells.

Here we describe differences in the formation of the epinephrine-induced Ca2+ transients between parent and Ki-ras-transformed NIH3T3 fibroblasts. These transients proved to be the results of an efflux from both the thapsigargin-sensitive and -insensitive intracellular pools. While the epinephrine-induced detachment of the ras-transformed cells might be due to cytoskeletal and/or cell-matrix alterations.

3T3 Cells↗
PubMed1993

The binding of diazepam in the mitochondria of Tetrahymena pyriformis as detected by quantitative high resolution autoradiography.

Tritiated diazepam accumulates mainly in the mitochondria of the unicellular Tetrahymena. This is the case in both a single (the first encounter) and a repeated (one day or a week after the first) administration of the drug. When imprinting of Tetrahymena by diazepam (the first encounter) is followed a week later by the administration of the labelled drug, the membranes of the vesicles, too, show the appearance of label. Regarding the studies presented here, the unicellular Tetrahymena also contain diazepam receptors in the mitochondria as suggested for cells of higher rank animals.

Animals↗
PubMed1993

Anabolic steroid (nandrolone) treatment during adolescence decreases the number of glucocorticoid and estrogen receptors in adult female rats.

The density of thymic glucocorticoid receptors and the density of uterus estrogen receptors (I) decreased significantly in adult female Wistar rats following nandrolone treatment at the age of six and seven weeks. There was no significant alteration of thymic glucocorticoid receptor density in males. Affinity of glucocorticoid and estrogen receptors did not differ from the controls significantly. The results demonstrate that the receptors of immature cells can be imprinted in adolescence similarly to those in the perinatal period and chemical substances capable of binding to the immature receptors can result in prolonged alteration of their binding character. This phenomenon should be taken into consideration especially in the case of nandrolone administration which can be used as a doping substance.

Animals↗
PubMed1993

Effect on inhibitors of glycoprotein synthesis (swainsonine, 1-deoxynojirimycin) on hormonal imprinting and lectin binding in Tetrahymena pyriformis.

Glycoprotein synthesis inhibitors (swainsonine = SW and 1-deoxynojirimycin = DNJ) influenced the insulin binding, insulin provoked hormonal imprinting and lectin binding of Tetrahymena. Insulin binding was increased and lectin binding decreased by both of them immediately after treatment, however, SW decreased insulin binding and both of them increased lectin binding after 24 h. SW inhibited, DNJ allowed the development of insulin imprinting. This means that the disturbance of glycosylation in general does not influence, but the blocking of mannosidase II disturbs the process of imprinting.

1-Deoxynojirimycin↗
PubMed1993

Uterus estrogen receptors' binding capacity is reduced in rat if exposed by benzpyrene neonatally.

During the critical period of receptor maturation within the first 5 days after birth female rats were treated with benzpyrene three times and their uterus estrogen receptor characteristic were examined in adulthood. Estrogen receptor density decreased significantly. There was no alteration in receptor affinity. Present experiment draws attention to the disadvantageous effect of aromatic hydrocarbons coming from the polluted air on steroid receptor development.

Animals↗
PubMed1993

The role of receptors of the plasma membrane and nuclear envelope in the failure of insulin imprinting in starving Tetrahymena.

Starvation for 2 h does not disturb the insulin binding of Tetrahymena. At the same time imprinting does not develop at the first encounter with insulin and a down regulation is observed after 168 h. Starvation for 2 h reduces the insulin binding of the nucleus to the half value after starvation for 24 h and this change in binding becomes settled by 48 h. Imprinting is not elicited either in the nuclear membrane. The down-regulation can be observed also after 48 h but it is not present in the 168-h measurements. The experiments emphasize the increased sensitivity of binding sites of the nuclear envelope and the role of it in the development of imprinting.

Animals↗
PubMed1993

Pheromone and insulin induced chemotaxis in Tetrahymena.

Cytodex spheres impregnated with insulin had a repellent effect at the first encounter and an attractive effect at the second encounter with Tetrahymena pyriformis. Tricosene, one of the two pheromones investigated had a positive chemotactic effect at the first encounter with the cells and this effect was increased following pretreatment (imprinting) with tricosene. Bornyl acetate expressed a negative effect on first use and was neutral on imprinted cells. The experiments demonstrate that not only hormones but also pheromones can serve as signal molecules for Tetrahymena. Moreover, the development of imprinting was observed. The effects and the imprintability were not a general characteristic of the pheromones which originate from the individual characters of the molecules. The development of imprinting can alter the direction of the effect of stimulus mediated by receptors.

Animals↗