Effect of compounds acting on gap junctions and membrane fluidity on the course and cell-to-cell transmission of hormonal imprinting in cell culture.
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Cell Communication↗
Biomedical subjects
G Csaba
Publications and source records attributed to G Csaba.
Acceleration of the internalization of ligand-bound membrane DNA by thyroxine treatment in macrophages.
The localization of membrane DNA and the binding and internalization of DNase-colloidal gold complex were examined in mouse peritoneal macrophages in presence and absence of thyroxine (T4). Preexposure to the hormone for 5 to 10 min caused no change relative to the control but preexposures for 30, 60, and 90 min accounted for an increase in the ligand binding capacity, aggregation of the DNase-gold particles on the cell surface, and appearance thereof in coated pits, coated vesicles, smooth vesicles and, finally, inside lysosomes. After 30 min preexposure to T4, subsequent 10 min treatment with the DNase-gold complex was as effective as 1 h treatment had been without T4.
Animals↗
Imprinting with oxytocin and vasopressin in Chang liver cell cultures: hormonal overlap, binding and influence on cell division.
In Chang liver cells the administration of oxytocin and vasopressin as well as the combined application of the two hormones will result in a positive binding imprinting for oxytocin and a negative binding imprinting for vasopressin. The hormones are able to increase the mitotic capacity of the liver cells even without previous imprinting, both in the case of treatment for 4 hours and for 24 hours; the change, however, is more marked in the case of treatment for 4 hours. Treatment for 24 hours results also in some functional imprinting.
Cell Division↗
Data on the evolution of hormones. Investigations on imprinting evoked by oligopeptides exhibiting no hormonal activity.
According to the present state of art, imprinting can also be evoked by di-, tri-, tetra- and heptapeptides exhibiting no hormonal activity, i.e., pretreatment with some of the oligopeptides leads to an enhancement of further hormone binding. Administration of symmetric and asymmetric molecules containing alanine resulted in positive, and negative imprinting respectively. The length of the molecule had no effect on the possibility of imprinting to develop. At the same time, the extent of imprinting evoked by molecules having no hormonal activity was approximately half of the imprinting seen in previous experiments when molecules having hormonal activity were applied. This observation indicates that in the phenomenon of development into a hormone the ability to evoke imprinting (to develop receptor memory) may be important. Thus, the development into a hormone is not an accidental event.
Animals↗
The effect of hormonal imprinting on 3H-steroid incorporation of Tetrahymena pyriformis.
Steroid hormones are incorporated by Tetrahymena, and appear intracellularly in both cytoplasmic and intranuclear localizations. At primary interaction with the steroid, incorporation was the greatest at 10 min, whereas at the second interaction it tended to increase with time. The Tetrahymena cells preexposed to a steroid incorporated a greater amount of it at the second exposure, owing presumably to the induction of steroid receptors at the first interaction.
Animals↗
Effects of hormones on the multiplication of the heterotrichous protozoon Blepharisma undulans stein.
The division rate of Blepharisma undulans is reduced by insulin treatment and increased by diiodotyrosine, diiodothyronin, histamine, serotonin or prednisolone treatment. In a later phase, the protozoa treated with histamine or prednisolone died. After insulin was deprived, the division rate strikingly increased as compared to the control cells, whereas the enhanced growth of the cells pretreated with any of the other hormones, except serotonin, continues in the absence of the hormone until the end of the observation period. The division rate of cells pretreated with serotonin decreased in the absence of the hormone. The cells of enhanced division rate hardly influenced by a second encounter with the same hormone, even insulin did not exert its characteristic negative effect. The fact that serotonin and insulin act in another way than do the other hormones suggests that the cell response is hormone-specific.
Animals↗
Influence of neonatal treatment with porcine insulin (hormonal imprinting) on the receptor binding of insulins of porcine, rat and human origin.
A single neonatal insulin treatment in the male rat decreases, whereas in the female rat it increases, the number of insulin receptors detected at the age of one month. No difference could be observed in affinity. The extent of the binding of rat, porcine and human insulin is different (the binding of human insulin is the most pronounced), meanwhile the alterations evoked by neonatal treatment are basically identical.
Animals↗
Hormonal imprinting and damages caused by fetal steroid treatment. Influence of fetal treatment with pregnancy-protecting steroids (allylestrenol, diethylstilbestrol) on the effect of gonadotropin administered to cockerels perinatally and at the age of six weeks.
Single fetal (9th day) treatment with either diethylstilbestrol (DES) or allylestrenol (AE) caused a considerable decrease, both at the age of five days and six weeks, in the weight of the testicles and the diameter of the seminiferous cords, while the ratio of spermatogonia to primary spermatocytes increased. When measured either at the age of five days or six weeks, gonadotropin treatment [a combination of follicle stimulating hormone (FSH) and luteinizing hormone (LH)], administered twice daily for three days after the hatching, led to an increase in the above-mentioned parameter and to a shift in the cell ratio towards the control value. However, the absolute value of the controls treated with FSH-LH was by far not reached. The effect of perinatal treatment could be detected even in adulthood, namely, at the age of five days the response capability was relatively weak in the cockerels treated with DES and AE, while high responsiveness was observed at the age of six weeks. In some cases the relative value of the increment exceeded even that of the control; however in absolute term it was well below the control. On the basis of these experiments it might be concluded that hormonal imprinting evoked by FSH-LH treatment also occurs in the gonad damaged by DES and AE. The setting in of imprinting ameliorates the damages caused by DES and AE and increases the response capability of the cells.
Allylestrenol↗
Imprinting by non-signal protein molecule in Tetrahymena.
Bovine serum albumin (BSA) enhances the division of Tetrahymena and leaves negative imprinting. In consequence, a repeated meeting with BSA 1, 2 or 3 weeks after the first one is followed by a significantly reduced division rate of Tetrahymena cells. The imprinting is fairly specific for BSA; the division rate was not influenced significantly by either human serum albumin or an anti-rabbit sheep immunoglobulin.
Animals↗
Enhancement of cilia regeneration by hormone treatment of Tetrahymena.
Regeneration of cilia of deciliated Tetrahymena was modified by hormones added to the nutrient medium; it was enhanced by serotonin (an amino-acid type substance), insulin (a polypeptide-type hormone) and prednisolone (a steroid-type hormone). Diiodotyrosine, another amino-acid type hormone, did not influence regeneration. Prednisolone, a hormone morphogenetic in mammals appeared to be the most active in regenerating cilia.
Animals↗
Role of the time factor in the development of hormonal imprinting of insulin receptors in Chang liver cell cultures.
Chang liver cells were pretreated with insulin for 5, 10, 20 and 60 minutes, and 4 and 24 hours after the treatment the binding of FITC-labelled hormone was measured. Hormone binding decreased after 5 minutes treatment, while longer treatments the binding increased considerably. The binding of hormone, at 4 hours investigation, to the nuclear membrane increased more markedly than in plasma membrane, indicating the important role of the imprinting of nuclear membrane. At 24 hours, the increased binding capacity is more characteristic for the plasma membrane.
Animals↗
Effect of protease substrates on insulin imprinting. Experiments with Tetrahymena and Chang liver cells.
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Animals↗
Effect of glycosylation inhibitors on the binding of insulin and lectins and on hormonal imprinting in Tetrahymena.
Treatment of the unicellular Tetrahymena with inhibitors of glycosylation (glucosamine or 2-fluoro-2-deoxy-D-glucose) leads, with a few exceptions, to enhancement of the binding of FITC-labelled insulin and lectins (Con-A, Helix, Datura). The development of insulin-evoked imprinting (i.e., the enhancement of binding at subsequent contacts) is not prevented by the administration of glucosamine. Meanwhile the administration of fluoroglucose results, on its own, in enhanced binding. This increased binding capacity cannot be further enhanced by imprinting.
Animals↗
Binding overlap and internalization of gonadotropin and thyrotropin in neonatal rat testicle and ovary cell cultures and the Chinese hamster ovary (CHO) cell line.
Colloidal-gold-labeled gonadotropin and colloidal-gold-labeled thyrotropin were bound by Chinese hamster ovary (CHO) and primary neonatal rat ovary and testicle cell cultures in the same sites and in the same quantities. The conditions of internalization and the intracellular fate of the bound gold-labeled hormones were also similar in every respect. Pretreatment with either hormone imprinted the cells also for the related hormone, as judged from the increased binding and internalizing capacity of the pretreated cells for either hormone, and from identical patterns of post-binding receptor aggregation.
Animals↗
Influence of pituitary hormones (hCG, TSH, Pr, GH) on testosterone level and on the functional activity of the Leydig cell in rat fetuses.
One day after the cessation of treatment the Leydig cells of the fetuses of pregnant rats, treated between the 11th and 15th or the 16th and 20th days of gestation, reacted to pituitary hormones. This finding indicates that both the receptors and the postreceptor mechanisms were in operative state. The effect of the thyrotropic hormone (TSH) overlaps the effect of related gonadotropic hormone (hCG), although this effect becomes smaller from the 21st day. The parameters investigated - the spectrocyto-fluorimetrically measured RNA-DNA ratio and the plasma testosterone level - ran generally in parallel. Similarly to the above-mentioned hormones, prolactin also increased the testosterone level (though to lesser degree than hCG and TSH did), however, while it increased the RNA level but at the age of 16 days, it decreased it the age of 21 days. Somatotropin (GH) also increased somewhat the testosterone level; however, the effects of the two related hormones (Pr and GH) fell far beyond the effect of either TSH or hCG.
Animals↗
Effect of inhibition of endocytosis, recycling and lysosomal activity on the insulin binding capacity and imprintability of Tetrahymena.
Dinitrophenol (DNP), an inhibitor of endocytosis of hormone receptors, Tris, an inhibitor of recycling and chloroquine, an inhibitor of lysosomal degradation, all decreased the binding of insulin and inhibited the development of hormonal imprinting in Tetrahymena. The effects of DNP and Tris seemed to be similar even quantitatively. The effect of chloroquine proved to be somewhat different, it appeared later, was more pronounced after 24 hours and more marked when insulin was also administered. Combined administration of Tris + DNP inhibited the binding of insulin but this inhibition was the one which disappeared most completely after 24 hours and the one where the inhibition of imprinting was the most pronounced. Tris + chloroquine led to severe destruction of the cells. The conclusion has been drawn that the inhibition of membrane circulation inhibits not only the hormone binding but also the development of imprinting in Tetrahymena.
2,4-Dinitrophenol↗
Effect of the absence of neonatal testosterone imprinting on the activity of the microsomal enzyme system and on the dexamethasone binding of the thymus in adulthood.
Healthy and neonatally castrated male rats were treated with testosterone twice perinatally, while other groups were treated with testosterone also in adulthood or received testosterone only in adulthood. Castration resulted in a moderate (but in some instances significant) decrease of PSMO (polysubstrate monooxygenase) level measured in adulthood. The decrease could partially be compensated by perinatal testosterone treatment. Further testosterone treatment administered in adulthood did not result in further alteration when compared either with the controls or with the neonatally treated animals. However, since in the controls the second testosterone treatment (following the neonatal one), had a decreasing effect, therefore the testosterone treatment administered in adulthood was responsible for the disappearance of the difference between the castrated animals and the controls treated both perinatally and in adulthood. On the basis of these findings it seems likely that the perinatal presence of testosterone plays a major role in the development of enzymatic imprinting and thus, in securing the capability of the liver to split testosterone in adulthood. Since testosterone influences the glycocorticoid receptors of the thymus (presumably by its overlapping effect), so the amount of free glycocorticoid receptors is always higher in the animals castrated neonatally than in the controls. Conversely, neonatal testosterone treatment somewhat increases the number of receptors detectable in adulthood.
Animals↗
Why do hormone receptors arise? An introduction.
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Animals↗