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Biomedical subjects

G Csaba

Publications and source records attributed to G Csaba.

At least 415 records · Page 23Linked to original sources
PubMed1981

FSH-TSH functional overlap in cockerel testicle. Durable amplification of the hormone receptors by treatment at hatching.

Functional overlap of FSH and TSH in cockerel testicle is expressed by alteration of testicular weight and canalicular diameter length. While on neonatal exposure TSH was more active than FSH, at five weeks of age both hormones developed an equal action. A single neonatal exposure to FSH had a durable effect on testicle weight and canalicular diameter, while the effect of post-hatching TSH persisted only in respect of the second parameter. A single neonatal exposure to TSH failed to amplify TSH effect on a second exposure at five weeks of age, while neonatal TSH and FSH treat equally enhanced the effect of FSH given at five weeks. This suggests that under given conditions, perinatal hormone excess may account for lasting amplification of the receptor(s) not only in respect of the adequate hormone, but also in respect of a related hormone, hormone-like material or analogon.

Age Factors↗
PubMed1981

Experimental study of hormone receptor development in a unicellular model system.

It was shown earlier that diiodotyrosine (T2) stimulates the growth of Tetrahymena. In the present study clonal populations of Tetrahymena, derived from subcultures propagated in the presence of T2, showed a highly significant increase of intra-clone variance over the control, while inter-clone variation was significant, but not decisive. This suggests that genetic factors play a smaller role in the development of the cell membrane receptor pattern tha the genetic variability of the membrane itself, which seems to account for the stabilization of the adequate receptors on first exposure to a hormone.

Analysis of Variance↗
PubMed1981

Effect of histamine and histamine antagonists on the glycogen content of Tetrahymena.

The glycogen content of Tetrahymena pyriformis was analysed by a cytophotometric method. Histamine and histamine antagonists were found to influence the glycogen content. It increases after acute histamine treatment, while it decreases after 4 days incubation with histamine. The H2 receptor antagonist methiamide was more effective than histamine, while the H1 receptor antagonist phenindamine had no effect on the glycogen content. The effect reflects the similarity or dissimilarity of the chemical structure of the antagonists and of histamine. Subdivision of the cytophotometric results indicated that all of the protozoa react to histamine or to its antagonists, but all agents increased the number of glycogen-rich Tetrahymena.

Animals↗
PubMed1981

Histamine-content of Gomori-positive cells in the rat thymus.

As revealed by a Reinecke-salt histochemical reaction and by immunocyto-chemistry, the Gomori-positive cells in the rat thymus contain histamine. The identity of Gomori-positive and histamine-containing cells was shown in histological preparations and tissue cultures.

Animals↗
PubMed1981

The effect of adrenocorticotropic hormone (ACTH) on embryonic chicken gonads.

Chicken embryos were exposed to a single dose of adrenocorticotropic hormone (ACTH) on the 15th day of the incubation period. Five days later, the female embryos showed a significant increase in ovarian weight, ovarian thickness and oocyte count. In contrast, the male embryos showed a significant decreased in testicle weight, seminiferous cord diameter and gonocyte number. The opposite response of testes and ovaries is discussed.

Adrenocorticotropic Hormone↗
PubMed1981

Effect of sympathomimetic substances and analogues on tail absorption of frog larva.

Similarly to the effect of T3, the tail absorption of frog larvae (Rana arvalis) was stimulated in vitro by the sympathomimetic agents adrenaline, isoproterenol, ephedrine and the adrenaline analogue MMT. The effect of T3 administration was not inhibited by adrenaline, isoproterenol and MMT, but it was by ephedrine and T3 pretreatment. The adrenaline and isoproterenol effect manifested itself after early administration, but not after late and while ephedrine and MMT were effective at long-term administration, even it administered at a later time. Our experiments draw attention to the metamorphotic effect of substances capable of binding to beta-receptors. Their effect may be explained partly by the increase in the cAMP level, partly by a relationship existing between the beta-receptor and the T3 receptor.

Animals↗
PubMed1981

Morphogenetic effect of cAMP during the metamorphosis of the frog larva.

In an in vitro system, the tail absorption of the frog larva was significantly stimulated by cAMP more intensely than by T3. Theophylline, an inhibitor of cPDE, had no effect and failed to enhance, even decreased the effect of T3. It may be supposed that T3 does not act through a cAMP mechanism, but the tail absorption can be influenced by cAMP in a direct way.

Animals↗
PubMed1981

Receptor development and hormone actions. Effect of insulin and epinephrine on the glycogen content of newborn rat liver cultures.

In the 9-day cultures of liver cells isolated from newborn rats epinephrine was found to increase the number of glycogen containing cells, and caused an elevation of the glycogen content of individual liver cells. Insulin treatment had a weak effect on the number of glycogen containing cells and its effect on intracellular glycogen content was negligible. The experiments indicate that the epinephrine receptor develops in the fetal period and is reactive in the newborn animal, while the insulin receptor is not. It was remarkable that in this period of life and under in vitro conditions the effect on cellular glycogen deposition of epinephrine and insulin is similar.

Aging↗
PubMed1981

Effects of mammalian hypophyseal hormones: gonadotropins, thyrotropin and adrenocorticotropin, on the embryonic development of 8-days chick embryo gonads.

When injected into chick eggs on the 8th day of incubation, gonadotropins (FSH + LH) were shown to stimulate the gonadal development on the 20th day of embryogenesis in both sexes. An increase in the testicular weight, in the seminiferous cord diameter as well as in germ and Sertoli cell number was observed in males. Similarly an increase in ovarian weight, in ovarian width, in cortical thickness and in the number of oocytes was reported in females. By contrast, thyrotropin (TSH) and adrenocorticotropin (ACTH) caused a noticeable decrease in gonadal development in both males and females as compared to the controls or to the gonadotropin-treated groups. It is concluded that the gonads of 8 days chick embryo have the capacity to respond to gonadotropic stimulation and not to the other hypophyseal hormones (TSH or ACTH). This suggests the possibility that at this early stage (8 days of incubation) the external specific hormone could induce its future hormone receptors.

Adrenocorticotropic Hormone↗
PubMed1981

Permanent amplifying effect on the cockerel gonad of hypophysis hormones (FSH, TSH) administered at hatching.

The effect of TSH and FSH was studied by quantitative histological analysis of the gonads in five-week-old cockerels pre-treated with these hormones at hatching. It was concluded that (1) hypophyseal hormones of similar molecular structure are not fully specific in immature animals. At five weeks both FSH and TSH enhance spermatogonium division and spermatogenesis, and increase the number of Sertoli cells. (2) While a single post-hatching dose of hormone has no effect on germinal cells as studied in the fifth week it increases the number of Sertoli cells (3) post hatching FSH-treatment facilitates the effect of hormone treatment at five weeks, amplifying the effect of FSH slightly more than that of TSH. Post hatching TSH-treatment also amplifies the effect of FSH administered at five weeks but does not influence the effect of five-week TSH-treatment on germinal cells. (4) The present results have corroborated earlier findings based on the measurement of gonadal weight and tubule diameter.

Aging↗
PubMed1981

Overlapping effect of thyroid-stimulating hormone and follicle-stimulating hormone on the thyroid gland in baby chicken.

Follicle-stimulating hormone (FSH) although quantitatively less effective than thyroid-stimulating hormone (TSH) in the thyroid gland, overlapped with the actions of the latter regarding the indices tested. Thus, it increased the follicular diameter and height of epithelial cells. These findings appear to support our earlier observation demonstrating an overlapping effect of tropic hormones in the gonads and suggest that the overlapping action of tropic hormones with related structure is a general phenomenon in the perinatal period.

Animals↗