Histidine decarboxylase deficiency in gene knockout mice elevates male sex steroid production.

Histamine is synthesized in cells by histidine decarboxylase (HDC). HDC-deficient knockout (KO) mice lack functional HDC and histamine in the tissues. In the present study we used this in vivo model for studying the role of HDC deficiency in the regulation of male steroid hormone metabolism. In agreement with earlier studies showing the lack of effects of central histamine on the basal secretion of gonadotrope hormones, we found no difference with in situ hybridization in the expression of GnRH in the hypothalamus of wild type and KO mice. The tissue concentrations of testosterone and several androgenic steroids were significantly elevated in the testes but not in the adrenal glands of HDC-KO mice. In contrast, serum estradiol levels failed to show a significant difference between the two groups. The weight of the testes was significantly smaller in both 7-day-old and adult KO mice. The ultrastructure of the adult testis indicated elevated steroid synthesis with more tightly coiled membranous whorls in Leydig cells. The present results suggest that changes in reproductive functions and sex steroid secretion in male HDC-KO mice are not due to altered hypothalamic GnRH expression but are probably related to definite modifications during fetal development of KO mice reinforced later by the lack of the effect of peripheral histamine. This may provide in vivo evidence that peripheral histamine is an important regulatory factor of male gonadal development during embryogenesis and of sex steroid metabolism later in adulthood.

Elevated hepatic glucocorticoid receptor expression during liver regeneration in rats.

In rats within the first week of partial hepatectomy reconstruction of the normal histological structure of the liver already starts. To approach the possible role of endogenous glucocorticoids in the process of regeneration we measured the changes in the expression of steroid glucocorticoid receptor gene after various regeneration intervals. After partial hepatectomy, between 0.5 168 hours from the surgery, the gene expression (mRNA) of glucocorticoid receptor was determined by reverse transcription followed by PCR and normalized to that of glycerolphoshate dehydrogenase. Two peaks of glucocorticoid receptor mRNA were detected first, between 3 and 6 hours (first peak) and a second between 24 and 36 hours. Immunoreactive glucocorticoid receptor was detected by immunohistochemistry using monoclonal anti-glucocorticoid receptor. Three days after the surgery immunohistochemical studies showed substantially more immunoreactive GcR protein in the regenerated liver than in the controls. These semiquantitative data provide evidence suggesting elevation of glucocorticoid receptor expression during regeneration of liver at mRNA and protein levels.

Study of histamine effects on phagocytosis and enzyme secretion of Tetrahymena pyriformis.

1. The biogenic amine histamine develops effects not only in mammalian cells and tissues but in ciliated unicellular Tetrahymena as well. In addition to binding and internalization of labelled histamine, low concentrations can stimulate the phagocytosis of cells in inorganic salt solution. 2. In inorganic solution Tetrahymena cells secrete acid hydrolases to the medium. High concentration of histamine (10 mM) decreases the secretion of three investigated acid hydrolases in a different manner. We think that in this process the primary determinant is the alkaline character of histamine. 3. The effect of histamine on phagocytosis differs from the effect on secretion since the low, physiological concentration of histamine stimulates phagocytosis, the higher concentrations inhibit it. In the background of these effects possibly the hormone character is dominant. It is supported by the fact that histamine antagonists influence the process differently.

The relationship of the endoplasmic reticulum to the Golgi complex in Tetrahymena pyriformis.

The endoplasmic reticulum (ER) and the closely connected, single dictyosomal Golgi apparatus of Tetrahymena pyriformis cells showed random distribution in the cytoplasm. Ribosomes were evident, and coated vesicles pinched off from the ER were seen. The membranes of the endoplasmic reticulum generally formed a tube-like structure, although after histamine treatment multiple, folded and circular structures were observed. The number of coated vesicles detaching from the endoplasmic reticulum increased as a result of histamine treatment.

Nucleolar changes in the oocytes of newborn rats treated with follicle stimulating hormone (FSH).

In the ovaries of newborn rats the exogenous follicle stimulating hormone (FSH) given in a large dose leads to the appearance of uncommon structures in the nucleoli of the oocytes. Fuzzy filaments sometimes with chiasma-like connections appear and ring-like structures in connection with, or independent of, the nucleoli are seen. The results demonstrate the possible appearance of a morphological response of oocytes to FSH prior to any detectable biochemical or receptor binding evidence.

The effect of thyrotropic hormone (TSH) on the thyroid gland of the newborn rat. An electron microscopic study.

The activity of the thyroid gland of the newborn rat is influenced by the treatment of TSH. Shortly after hormone injection, its effects can be detected in the synthesis and storage of the colloid. In a longer term (30 min and 60 min) the morphological signs of resorption and secretion are evident. At this early age the cellular compartments involved in the secretory pathway of the cells are still not complete in maturation (less developed Golgi complex, missing secretory vesicles and micropinocytotic vesicles). According to our results, even TSH administration cannot influence this picture in the short term. Our work supports the intracellular way of folliculogenesis, and the TSH action as a promoter in this way.

[Comparative light microscopic, scanning-electron microscopic and electron microscopic studies of the effect of experimental interventions by surgical scalpel, electrocautery and CO2-laser beam in the oral cavity]. / A sebészi szikével, az elektrokauterrel és a CO2-lézersugárral kísérletesen a szájüregben létrehozott beavatkozások hatásának fénymikroszkópos, scanning-elektronmikroszkópos és elektronmikroszkópos összehasonlító vizsgálata.

Tissue effect interventions by means of surgical scalpel, elecrtokauter and CO2-laser ray in the mouth cavity of 20 white rats has been examined. According to their light microscopical examinations both the laser and the electrokauter caused thermal injuries taking place in typical zones while by the scalpel the cut surface in rendered ragged. The band-width of the thermoinjury caused by the kauter is a multiple of that caused by the laser. It has been proved by means of scanning electronmicroscopical examinations that interventions by means of laser result in sharp wound borders, the wounds cut by means of kauter are characterised by the presence of a great number of carbonized specks while by means of the scalpel a mechanical tear of the tissues is brought about. By means of electronmicroscopical examination the characteristics of the typical thermoinjured zones are described. It has been established that in the case of laser the injury of the ultra-structure extends to 400 microns while in case of electrokauter it reaches a width of 1500 microns. The excellent haemostatic effect brought about by the thermoeffect by means of the laser, in contrast to the broad thermoinjured zone caused by the kauter, is obtained at a very mild thermoinjury.

Internalization of receptor and hormone after hormonal imprinting, as detected with colloidal gold labeled insulin in cultures of a permanent liver cell line.

The intracellular localization of internalized colloidal gold-labeled hormone differed markedly between Chang liver cells pretreated and not pretreated with insulin. While the non-imprinted cells bound little hormone in the coated pits and internalized it mainly inside smooth vesicles, the imprinted cells bound the bulk of hormone in coated pits and coated vesicles. Later the label appeared inside the lysosomes and in the imprinted cells it was abundantly present also in extra-lysosomal localizations, mainly on the nuclear membrane and inside the nucleus. These observations disclosed some new information on the internalization of the receptor-hormone complex, and on the mechanism of hormonal imprinting as well.

Influence of deciliation and ciliary regeneration on hormonal imprinting in Tetrahymena. Observations on the 'localization' of imprinting.

Imprinting induced in Tetrahymena with insulin is not abolished by deciliation. No imprinting occurred in deciliated cells exposed to insulin at 1 or 2 h of regeneration. However, imprinting did occur if Tetrahymena was exposed to insulin after 3 h of regeneration. It appears that while presence of cilia is a prerequisite of imprinting, the pertinent information is not, or not exclusively stored in the cilia.

The ultrastructure of adrenocortical (interrenal) cells of normal and ACTH-treated chick embryos.

The ultrastructural features of the interrenal cells have been studied in 20-days-old chick embryos following the administration of adrenocorticotropin (ACTH), on the 8th or 15th day of incubation. The interrenal cells of normal embryos contain more SER than RER, mitochondria with tubular cristae, lipid droplets and Golgi complex. Adjacent cells had numerous regions of pentalaminar fusion and intermediate junctions. Neither a precise organization of medullary tissue in relation to interrenal tissue nor any structural differences between interrenal cells were found. Changes in the fine structure of the interrenal cells following ACTH treatment were extensive. The organelles that are known to be involved in the biosynthesis of steroids displayed structural modifications. These were mainly SER, mitochondria, and lipid droplets. Changes were also noticeable in the Golgi complexes, membrane-bound dense bodies (especially in 15 days treated embryos). These results indicate the well developed organelles in the interrenal cells of 20-days-old embryos, and their capacity to respond to ACTH stimulation as early as the 8th day of embryogenesis.

Coated pits and coated vesicles in unicellulars (Tetrahymena, Crithidia) and in Hydra.

Coated pits and coated vesicles were observed in the ciliated unicellular Tetrahymena, in the flagellated unicellular Crithidia, and in Hydra. In the unicellulars the coated structures localized for the most part near to the origin of cilia or flagella, and many were present around the Golgi complex, whereas in Hydra they occurred in nonspecific random locations. Since the membrane receptors of the unicellulars serve originally as food receptors, the coated pits and vesicles are presumably involved in food selection, and represent as such the primitive form of the receptor-mediated ligand internalization mechanism operative in higher organisms.

Effect of high-dose thyrotropic hormone treatment on the cells of the newborn rat thyroid.

Newborn rats were given 5 I.U. thyrotropic hormone (TSH) either in a single dose or in daily 1 I.U. doses for 5 days. The treatment resulted in the activation of only certain cells of the follicular epithelium. This suggests that the thyroid is responsive in newborn age but not all its cells react. The differences in the response to TSH may be due to different timing of receptor maturation, to the phasic nature of response and to the uneven presence of receptors. It is assumed that cells possessing receptors multiply to form the mature tissue.

Histochemical demonstration of glucagon and serotonin by a fluorescent method in the rat submaxillary gland.

The submaxillary glands of young rats were examined in vivo and in vitro. Yellow fluorescence in some cells treated with o-phthalaldehyde was observed and they yielded a positive reaction on staining with phosphotungstic acid haematoxylin indicating the presence of glucagon. These cells were localized between secretory endpieces of the gland. In rats treated with L-5-hydroxytryptophan (L-5-HTP) cells similar in shape and size showed yellow fluorescence after the action of formaldehyde vapour. The results of histochemical studies and ultrastructural analysis seem to indicate the presence of cells similar to APUD endocrine cells in the rat submaxillary gland.

Effect of glutaurine on the pineal gland of the rat.

Glutaurine (gamma-L-glutamyl-taurine), the recently discovered hormone of the parathyroid enhances the aggregation and subsequent degeneration of mitochondria in the pinealocyte processes of the rat pineal gland. It also stimulates autophagy, probably through its general lysosome activating effect.

Localization of concansvalin-A binding sites in Tetrahymena by scanning electron microscopy.

Binding sites of concanavalin-A were detected in Tetrahymena on the body ciliature, while the cell membrane itself and the oral ciliature failed to bind the lectine.

Concentration of dopaminergic fibres in the marginal zone of the bird retina.

Nerve fibres containing dense core vesicles of 100-160 nm diameter are concentrated in a narrow zone (near the ora serrata) of the marginal retina in the pigeon and the chicken. Synaptic junctions exist between terminals containing dense core vesicles and the most marginal ganglion cells; however, numerous fibres seem to end freely near the vitreous body or even penetrate the pars plana of the ciliary body. Histofluorescence demonstrates the aminergic nature of these fibres. Determination of catecholamines with the dansylation technique reveals six times more dopamine in the marginal than in the central retina, whereas the noradrenalin level is unchanged. The dopaminergic fibres originate in neurons of the innermost zone of the inner nuclear layer. The marginal localisation of these fibres apparently excluding any visual function seems rather to indicate a possible photoreceptor system involved in neuro-endocrine regulation.