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Biomedical subjects

G Csaba

Publications and source records attributed to G Csaba.

At least 325 records · Page 18Linked to original sources
PubMed1986

Influence of prenatal steroid exposure on neonatal gonadotropin imprinting. Effect of single and combined hormone treatments on the chicken ovary.

Chicken embryos treated with DES or AE at the 9th day of incubation showed postnatally an increase in ovarian mass, parenchymal zone thickness, follicle diameter and granulosa cell count. Perinatal gonadotropin treatment had a similar effect on these parameters in the control birds not receiving pretreatment, but had no influence on them in the birds pretreated with steroid. The tested ovarian parameters of the DES- and AE-pretreated birds still differed from the control at 6 weeks of age. Neonatal gonadotropin exposure induced imprinting in the birds not pretreated with steroid, to judge from an increased response (indicated by changed values of the tested parameters) to gonadotropin reexposure in adulthood. Similar, but considerably slighter changes were also shown by the steroid pretreated birds. It follows that in the birds prenatally exposed to AE or DES, supervening perinatal exposure to gonadotropin did not elicit greater changes than the prenatal exposure itself.

Allylestrenol↗
PubMed1986

The effect of bacterial endotoxin of phagocytosis of Tetrahymena and serotonin induced imprinting.

Endotoxin inhibited the phagocytosis of Tetrahymena pyriformis after a short exposure and, to a lesser degree, after repeated treatments during one week (about 35 generations). Endotoxin also prevented the development of serotonin imprinting. Detoxified endotoxin (Tolerin) affected the phagocytosis of Tetrahymena much less, indicating that the lipid-A part of the molecule may account for the membrane-toxic effect.

Animals↗
PubMed1986

Effect of prenatal and/or neonatal diethylstilbestrol (DES) or allylestrenol (AE) treatment on the postnatal development of the chicken ovary.

Chickens treated with allylestrenol or diethylstilbestrol in the egg on 9th day of incubation, or one day after hatching, or on both occasions, equally showed histomorphological indications of a distinct ovarian activation at 5 days of age, which was most pronounced in the twice-treated birds. A single steroid exposure at one day of age accounted for inhibition of ovarian activity at 6 weeks, presumably owing to a long-term effect on the hypothalamo-hypophyseal system, which begins to function from the 12th day of incubation.

Allylestrenol↗
PubMed1986

Hormonal imprinting by steroids: a single neonatal treatment with diethylstilbestrol or allylestrenol gives rise to a lasting decrease in the number of rat uterine receptors.

Binding of hormone by the uterine receptors of 6 week old rats treated with diethylstilbestrol (DES) or allylestrenol (AE) in neonatal age differed considerably from the controls. Both pretreatments accounted for a decrease in the number of Type II binding sites for estradiol without altering receptor affinity. It follows that steroids, too, are able to induce a hormonal imprinting during the critical stage of receptor maturation.

Allylestrenol↗
PubMed1986

Ouabain binding of the rat's heart muscle cells after neonatal glucocorticoid (triamcinolone) treatment.

In adult rats the ouabain-sensitive ATP-ase activity of the heart muscle as well as the amount of specifically bound 3H-ouabain decreased by 1/3 as a result of a single triamcinolone treatment undertaken in the neonatal period. Neonatal ouabain treatment did not alter the triamcinolone binding of the thymus of adult animals. The experiments again call attention to the phenomenon that the steroid hormones, even though specific for their target cells, are able to induce "alien" imprinting when administered in the neonatal period. They are also able to bind to steroid receptors of other cells altering, thereby, the responsiveness of these cells in adulthood.

Animals↗
PubMed1986

Reduced thymic glycocorticoid reception in adult male rats prenatally treated with allylestrenol.

The first-generation male offsprings of female rats treated with allylestrenol on days 7 and 14 of the pregnancy showed in adulthood a considerable decrease in thymic dexamethasone binding. The diminution of binding capacity was due to an about 50% decrease in the number of the thymic dexamethasone receptors, since receptor affinity for the hormone was not altered by the applied treatment. This experimental observation has called attention to the possible hazards of allylestrenol treatment commonly applied to pregnant women for averting imminent abortions.

Allylestrenol↗
PubMed1986

Influence of single neonatal treatment with allylestrenol or diethylstilbestrol on microsomal enzyme activity of rat liver in adulthood.

A single neonatal treatment of rats with a steroid (allylestrenol or diethylstilbestrol) did not alter the later activity of the hepatic microsomal (cytochrome P-450) enzyme system, but inhibited the inducer action of another steroid (testosterone) administered at the age of six weeks. This suggests that a hormonal imprinting-like mechanism also operates in the case of enzymes.

Allylestrenol↗
PubMed1985

Influence of the neonatal suppression of TSH production (neonatal hyperthyroidism) on response to TSH in adulthood.

Six-day treatment of neonatal rats with T3 or T4 resulted in a considerable depression of T4 production in response to exogenous TSH in adulthood. This supports the hypothetical conclusion that hormonal imprinting, i.e. the presence of the hormone and its interaction with the cell during the period of receptor maturation, is important for receptor amplification, which accounts for normal response to the hormone in adulthood.

Animals↗
PubMed1985

Induction of steroid binding sites (receptors) and presence of steroid hormones in the unicellular Tetrahymena pyriformis.

The unicellular Tetrahymena does not normally possess a steroid hormone (dehydroepiandrosterone, DHEA) or a glucocorticoid (dexamethasone) receptor, but both kinds of receptor can be induced in it by pretreatment (imprinting) with the adequate hormone. The specific receptors which arise are demonstrable experimentally. Examination of Tetrahymena cells for endogenous steroids by the radioimmunoassay (RIA) technique detected an appreciable concentration of DHEA and DHEA sulphate, and lesser concentrations of testosterone and estradiol in this unicellular organism.

Androgens↗
PubMed1985

Chemical reception mechanisms at a low level of phylogeny. Influence of polypeptide hormones and non-hormone polypeptides on the growth of Tetrahymena.

The polypeptide hormones insulin, glucagon, thyrotropin (TSH), pregnant mare serum gonadotropin (PMSG) and adrenocorticotropin (ACTH) stimulated the growth of the Tetrahymena, and the non-hormone polypeptides (bovine serum albumin (BSA), protamine) had a similar effect. Re-exposure after 24 h accounted for a greater growth stimulation than pre-exposure alone in cultures treated with TSH and PMSG, and re-exposure after 7 days had such effect in all polypeptide-treated cultures. It follows that the non-hormone polypeptides had a similar imprinting potential to the polypeptide hormone. The non-hormone polypeptides were also able to cross-imprint for one another, i.e. pre-exposure to one enhanced the binding capacity of the cells for the other on re-exposure, and vice versa. A single treatment with a polypeptide hormone or a non-hormone polypeptide did in itself stimulate the growth of the Tetrahymena for as long as 1 week.

Animals↗
PubMed1985

Electron microscopic localization and hormonal (diiodotyrosine) induction of adenylate cyclase in the Tetrahymena.

Normal Tetrahymena cells exhibited adenylate cyclase activity exclusively in association with pinocytotic vesicles, whereas those treated with diiodotyrosine (T2) for growth stimulation showed it in association with the cell membrane, and intracellularly inside many dense bodies. It appears that hormonally activable adenylate cyclase is an inherent component of the Tetrahymena.

Adenylyl Cyclases↗
PubMed1985

Effects of insulin and histamine in themselves and in combination on the glucose metabolism of Tetrahymena.

The glucose metabolism and the related intracellular processes of Tetrahymena pyriformis GL cells are measurably influenced by several hormones of higher organisms, among others by the endocytosis stimulating hormone histamine, and the glucose metabolism regulating hormone insulin. Histamine does not interfere with the glucose metabolizing action of insulin, but markedly enhances the utilization of glucose, to judge from a significant decrease in the PAS-positive (hexose) component of histamine-exposed Tetrahymena pyriformis GL cells.

Animals↗