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Biomedical subjects

G Csaba

Publications and source records attributed to G Csaba.

At least 127 records · Page 7Linked to original sources
PubMed1994

Immunocytochemical verification of the insulin receptor's specificity in the nuclear envelope of Tetrahymena. Comparison with receptors of the plasma membrane.

The unicellular Tetrahymena possess hormone receptors in the nuclear envelope similarly to higher rank animals. These receptors bind insulin and their specificity is detectable by monoclonal antibodies developed to insulin. The hormonal (insulin) pretreatment (imprinting) of the cell did not alter the binding capacity of the nuclear membrane, demonstrated by antibody-technique. The specific binding characteristics of the plasma membrane was demonstrated and this was significantly increased following imprinting. In the nucleus of Tetrahymena presence of insulin was not detected by immunocytochemical method.

Animals↗
PubMed1994

Influence of insulin on the movement of Tetrahymena pyriformis. Hormonal imprinting alters the velocity.

Treatment with insulin, cyclic adenosine monophosphate (cAMP) or theophylline, which uniformly influence the intracellular cAMP level, accounted for appreciable changes in the movement of Tetrahymena pyriformis. All applied treatments caused a quantitative decrease in the percentage of relatively rapid movements (straight and spiral swimming) and a proportional increase in that of slow movements (standing, turn, creeping). A single treatment with insulin caused a quantitative decrease in fast movements and a quantitative increase in slow movements also in the offspring generations and reexposure to insulin had a similar, but even stronger effect.

Animals↗
PubMed1994

Breastmilk can mediate chemical imprinting. Benzpyrene exposure during lactation reduces the thymic glucocorticoid receptor density of the offspring.

1. Prolonged benzpyrene treatment during lactation reduced the number of glucocorticoid receptors of offspring in adulthood significantly without altering the receptor affinity. 2. Dexamethasone treatment identical to benzpyrene exposure had no effect either on receptor number or affinity. 3. The results of the present investigations draw attention to the possible way of receptor alteration via breastmilk.

Animals↗
PubMed1994

Benzpyrene treatment in adulthood increases the testosterone level in neonatally steroid(allylestrenol)-treated male rats.

1. Serum testosterone level was significantly elevated in adult male rats after a single perinatal allylestrenol administration. 2. Benzpyrene treatment of adult rats perinatally treated with allylestrenol, did not cause changes 1 week after benzpyrene treatment, but 3 weeks later an extremely high serum testosterone level was found. 3. In control animals benzpyrene administration in adulthood did not influence the serum testosterone level either 1 or 3 weeks following the treatment.

Allylestrenol↗
PubMed1994

Effect of treatment with contraceptive steroids on the sexual behaviour of rats pretreated with benzpyrene or allylestrenol in fetal or neonatal age.

Treatments with contraceptive steroids significantly reduced the receptivity of adult female rats. This effect was not observed in ovariectomized females treated with high doses of estrogen and gestagen hormones prior to the investigation. The receptivity was also significantly reduced in rats treated with steroids (allylestrenol or benzpyrene) in their fetal or neonatal age, as it was demonstrated in previous experiments. The contraceptive treatment of the above described, pretreated adults resulted in improved function of receptivity, but it had no difference compared to the group which was only treated with anticoncipient. This means that neonatal treatment with allylestrenol or benzpyrene does not influence the effects of contraceptive steroids on the sexual behaviour (receptivity). The two effects are not additive.

Allylestrenol↗
PubMed1994

Effect of permanent starvation on the insulin receptors of the nuclear envelope of Tetrahymena.

Insulin receptors of Tetrahymena following a two-hour starvation (one cell generation) can bind the insulin similarly to the fed, control cells. The nuclear envelope of Tetrahymena cells which have already met the hormone (imprinted cells) can bind the insulin significantly stronger than the control. This binding capacity has a mild decrease after a two-hour starvation; after 18-hour starvation the decreasing effect is more expressed and reaches the control level. On the ground of the experiments it is probable that the insulin receptors of the plasma membrane and the nuclear envelope are identical.

Animals↗
PubMed1994

Change in insulin binding capacity of plasma membrane and nuclear envelope of Tetrahymena following a single long-term pretreatment and several short-term pretreatments (imprinting) with insulin.

Following insulin pretreatment (hormonal imprinting) of Tetrahymena cells there was an increased binding of insulin both in the plasma membrane and in the nuclear envelope of the offspring generations. A short (1 x 15 min) treatment did not produce imprinting in the plasma membrane but a 1 h treatment was sufficient. A similar short (1 x 15 min) treatment was enough to develop imprinting in the nuclear envelope and this is the treatment which induced the highest response. In the nuclear membrane there was a significant difference in the effect of 4 x 15 min and 1 x 60 min treatments but there was no effect in the plasma membrane. The effect of imprinting was observed after 48 h (16-20 generations). The repeated treatment of imprinted cells did not induce a further increase in the binding of the hormone.

Animals↗
PubMed1994

Tetrahymena cells distinguish insulin preparations according to either their amorphous and crystalline form or their bovine and porcine origin: aspects of hormone binding and chemotaxis in relation to imprinting.

Bovine insulin had a strong negative effect on the chemotaxis of Tetrahymena at the first encounter with the hormone. The crystalline porcine insulin proved to be neutral, while the amorphous porcine insulin had a significant positive chemotactic effect. At the second encounter with the hormone the presence of imprinting was detectable with bovine insulin and induced a significant positive chemotaxis. The chemotactic effect of amorphous porcine insulin was depressed while crystalline porcine insulin expressed the most significant positive chemotactic effect. In the binding of hormones there was unambiguous positive imprinting independently from the species specificity and from the physicochemical condition of the insulins. Tetrahymena discriminated at both the first and second encounters between the bovine and porcine insulins which differed in two amino acids. The imprinter capacity evident in binding was independent of the chemotactic preference and the imprinting embodied in chemotaxis.

Animals↗
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↗