Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    A radioautographic study on the mechanisms by which adrenal glucocorticoids play their permissive role in the biological activity of cyclic AMP in the liver cell (1974)
    Springer
    Cellular and molecular life sciences 30 (1974), S. 230-232 
    Details
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Riassunto I meccanismi che operano alla base dell'effetto «permissivo» dei corticosteroidi sulle azioni metaboliche dell'adenosin-monofosfato-3′,5′-ciclico (cAMP) sono stati indagati in colture primarie di fegato di Ratto. I risultati ottenuti indicano che i glucocorticoidi, mentre diminuiscono l'utilizzazione del cAMP nel nucleo degli epatociti, la aumentano a livello del citoplasma. Viene avanzata l'ipotesi che gli steroidi inibiscano la sintesi delle chinasi proteiche nucleari cAMP-dipendenti e/o il loro trasferimento nel nucleo e, contemporaneamente, stimolino la sintesi delle chinasi citoplasmatiche. Per converso, si è appurato, in parallelo, che il cAMP ha effetti alquanto limitati sul destino del cortisolo (e metaboliti) legato a proteine nella cellula epatica.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01934796
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Primary tissue culture of human adult adrenocortical cells. Methodology and electron microscopic observations on ACTH-deprived and ACTH-treated cortical cells (1974)
    Springer
    Cell & tissue research 155 (1974), S. 155-180 
    Details
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Man ; Primary cultures ; ACTH ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A method of primary tissue culture involving both disaggregation of cells by repeated exposure of small tissue fragments to a solution of trypsin, collagenase and hyaluronidase and explantation of the residual tissue fragments intermingled with isolated cells onto polyethylene discs, has been shown to be adequate for the prolonged maintenance (up to 30 days) in vitro of cells arising from decapsulated adult human adrenocortical tissue. The technique and its critical points are discussed. Adrenocortical cells were organized both as outgrowing columns from microexplants or as variously sized islets of monolayered cells. The ultrastructural features of ACTH-deprived adrenocortical cells (i.e., mitochondria with laminar cristae, endoplasmic reticulum mainly consisting of rough profiles, abundance of lipid droplets and β-glycogen particles) suggest that the cells dedifferentiate and retain practically no steroidogenic activity. After 2 days of ACTH-treatment, cultured parenchymal cells were found to be quite similar to the zona fasciculata elements of the normal human adrenal cortex. They were grouped in islets of about 50–100 cells. Rough endoplasmic reticulum had decreased, but smooth endoplasmic reticulum showed focal proliferation. The pleomorphic mitochondria with laminar cristae, transformed into a homogeneous population of round or ovoid mitochondria containing tubulo-vesicular cristae. Lipid droplets and glycogen particles were decreased in number. After 7 days of daily treatment with ACTH, the cortical elements, whose nucleus and cytoplasm seemed to be enlarged, were arranged in clusters formed by up to 300 monolayered elements, in which dividing cells were consistently observed. Their cytoplasm was filled with a meshwork of smooth reticulum tubules, in which scantly ribosome-studded profiles and occasional small stacks of granular cisternae were embedded. Mitochondria were similar to those of the 2 days ACTH-treated cultures. Lipid droplets and glycogen particles were absent. The functional significance of these structural changes as well as the possible mechanism underlying the differentiative effect of ACTH are discussed. Primary cultures of human adult adrenals are proposed as a new tool for studies into the physiopathology of the adrenocortical cells under carefully controlled experimental conditions. mis|It is a pleasure to acknowledge our thanks to Drs. F. Mantero and C. Eccher for kindly supplying the normal human adrenocortical tissue. Thanks are also due to Mr. G. Gottardo for his excellent technical assistance. mis|This work was partly supported by a contract with the CNR-Italy (C.T. 73.00663.04).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00221351
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Stereological and functional investigations on isolated adrenocortical cells: Zona fasciculata/reticularis cells of chronically ACTH-treated rats (1989)
    Springer
    Cell & tissue research 258 (1989), S. 43-51 
    Details
    ISSN: 1432-0878
    Keywords: Isolated adrenocortical cells ; ACTH ; Steroidogenesis ; Stereology ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphology and function of isolated inner (zona fasciculata/reticularis) adrenocortical cells of rats pretreated with ACTH for 3, 6, 9 or 12 days were investigated. ACTH treatment induced a notable time-dependent enhancement in the steroidogenic capacity (corticosterone production) and growth of inner cells. The volumes of cells, mitochondrial compartment, membrane space [the cellular space occupied by smooth endoplasmic reticulum (SER) membranes] and lipid-droplet compartment, as well as the surface area of mitochondrial cristae and SER tubules, were increased in relation to the duration of ACTH pretreatment, and showed a highly significant positive linear correlation with both basal and stimulated corticosterone production. The acute exposure of isolated cells to ACTH provoked a striking lipid-droplet depletion, the extent of which was linearly and positively correlated with stimulated corticosterone secretion. The hypertrophy of the mitochondrial compartment and SER are interpreted as the morphological counterpart of the enhanced steroidogenic capacity of inner adrenocortical cells, inasmuch as the enzymes of steroid synthesis are located in these two organelles, and it is well known that chronic ACTH exposure stimulates the de novo synthesis of many of them in vivo. The rise in the number of lipid droplets, in which cholesterol is stored, is interpreted as being due to the fact that, under chronic ACTH treatment, the processes leading to cholesterol accumulation in adrenocortical cells (exogenous uptake and endogenous synthesis) exceed those of its utilization in basal steroid secretion. Cholesterol accumulated in lipid droplets as a reserve material may be rapidly utilized after acute ACTH exposure to meet the needs of the enhanced steroidogenic capacity of adrenocortical cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00223143
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Growth stimulation and apoptosis induced in cultures of neonatal rat liver cells by repeated exposures to epidermal growth factor/urogastrone with or without associated pancreatic hormones (1986)
    Springer
    Cell & tissue research 245 (1986), S. 471-480 
    Details
    ISSN: 1432-0878
    Keywords: Neonatal hepatocytes ; Peptide mitogens ; Epidermal growth factor/Urogastrone ; Glucagon ; Insulin ; Cell proliferation ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In untreated primary cultures of neonatal rat liver kept in high-calcium (1.8 mmol/l), foetal bovine serum (10%v/v)-containing minimal essential medium (FBSMEM), the absolute numbers of hepatocytes did not change between day 4 and day 9 because ongoing cell loss was counterbalanced by proliferation of a discrete sub-population of the cells. By contrast, the number of stromal cells increased linearly with time. Growth of hepatocytes and stromal cells was differently affected by the daily addition, between day 4 and day 8 of culture, of fresh medium to which peptide mitogen(s) in concentrations ranging from 10-14 to 10-8 mol/l had been added. Epidermal growth factor/urogastrone (EGF/URO) with or without equimolar mixtures of glucagon and insulin, induced first hyperplasia of hepatocytes and stromal cells and then apopotosis (degeneration and death) of the progeny of the stimulated cells. By contrast, equimolar mixtures of glucagon and insulin caused a progressive increase in the number of hepatocytes and stromal cells unbalanced by any increase in cell death. At subphysiological concentrations glucagon, in synergism with EGF/URO and/or some other unknown heat-stable component of serum, acted as a trophic factor for hepatocytes. By contrast, insulin alone did not enhance growth of hepatocytes, but rather blocked the mitogenic effects of EGF/URO. The three hormones exerted neither mitogenic nor apoptotic effects when administered in a low calcium (0.01 mmol/l) FBS-MEM medium. These results reveal that EGF/URO may control the size of cell populations in neonatal liver by calcium-dependent mechanisms that make it unlikely to be a promoter of hepatocyte tumours. They also show that glucagon acts as a positive trophic regulator for hepatocytes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00218546
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    The effects of ageing on the morphology and function of the zonae fasciculata and reticularis of the rat adrenal cortex (1992)
    Springer
    Cell & tissue research 270 (1992), S. 265-272 
    Details
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Ageing ; Steroidogenesis ; Electron microscopy ; Morphometry ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphological counterpart of the well-known age-dependent marked impairment of glucocorticoid secretion of rat adrenals was investigated by use of morphometric techniques. For this purpose 4-, 8-, 16- and 24-month-old rats were studied. Despite the notable lowering of both basal and ACTH-stimulated production of corticosterone by collagenase-dispersed inner adrenocortical cells, ACTH and corticosterone plasma concentrations displayed significant increases with ageing. Zona fasciculata (ZF) and zona reticularis (ZR) showed a notable hypertrophy in aged rats, which was due to rises in both the average volume and number of their parenchymal cells. The hypertrophy of ZF and ZR cells was in turn associated with increase in the volume of the mitochondrial compartment and proliferation of smooth endoplasmic reticulum, i.e., the two organelles involved in steroid-hormone synthesis. All these morphologic changes, conceivably due to the chronic exposure to high levels of circulating ACTH, are interpreted as a response enabling ZF and ZR to compensate for their age-dependent lowering in glucocorticoid secretion. Stereology also demonstrated that ZF and ZR cells underwent a striking age-related lipid-droplet repletion. Lipid droplets are the intracellular stores of cholesterol esters, the obligate precursors of steroid hormones in rats. This finding is in keeping with the contention that the mechanism underlying the age-dependent decline in rat-adrenal glucocorticoid secretion mainly involves impairments of the utilization of intracellular cholesterol previous to its intramitochondrial transformation to pregnenolone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00328012
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Effects of prolonged sodium restriction on the morphology and function of rat adrenocortical autotransplants (1991)
    Springer
    Cell & tissue research 265 (1991), S. 35-41 
    Details
    ISSN: 1432-0878
    Keywords: Adrenal autotransplants ; Sodium restriction ; Mineralocorticoid hormones ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Regenerated adrenocortical nodules were obtained by implanting fragments of the capsular tissue of excised adrenal glands into the musculus gracilis of rats (Belloni et al. 1990). Five months after the operation, operated rats showed a normal basal blood level of corticosterone, but a very low concentration of circulating aldosterone associated with a slightly increased plasma renin activity (PRA). Regenerated nodules were well encapsulated and some septa extended into the parenchyma from the connective-tissue capsule. The majority of parenchymal cells were similar to those of the zonae fasciculata and reticularis of the normal adrenal gland, while zona glomerulosa-like cells were exclusively located around septa (juxta-septal zone; JZ). In vitro studies demonstrated that nodules were functioning as far as glucocorticoid production was concerned, while mineralocorticoid yield was very low. Prolonged sodium restriction significantly increased PRA and plasma aldosterone concentration, and provoked a marked hypertrophy of JZ, which was due to increases in both the number and average volume of JZ cells. Accordingly, the in vitro basal production of aldosterone and other 18-hydroxylated steroids was notably enhanced. The plasma level of corticosterone, as well as zona fasciculata/reticularis-like cells and in vitro production of glucocorticoids by regenerated nodules were not affected. These findings, indicating that autotransplanted adrenocortical nodules respond to a prolonged sodium restriction similar to the normal adrenal glands, suggest that the relative deficit in mineralocorticoid production is not due to an intrinsic defect of the zona glomerulosa-like JZ, but is probably caused by the impairment of its adequate stimulation under basal conditions. The hypothesis is advanced that the lack of splanchnic nerve supply and chromaffin medullary tissue in regenerated nodules may be the cause of such an impairment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318136
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Distribution and functional significance of the endothelin receptor subtypes in the rat adrenal gland (1997)
    Springer
    Cell & tissue research 288 (1997), S. 345-352 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Endothelins ; Endothelin receptors ; Adrenal gland ; Steroid secretion ; Catecholamine secretion ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Endothelins (ET) are a family of vasoactive peptides that act via two subtypes of receptors, named ETA and ETB. ET-1 binds to both ETA and ETB, whereas the isopeptide ET-3 preferentially binds to ETB. The localization of ETA and ETB receptors in the rat adrenal gland and their involvement in the adrenal secretagogue effect of ETs has been studied in vitro. Autoradiographic assessment of the selective displacement of [125I]ET-1, [125I]ET-3 and [125I]BQ-3020 (an ETB agonist) by BQ-123 or BQ-788 (specific antagonists of ETA and ETB, respectively) indicates that the zona glomerulosa and adrenal medulla possess both ETA and ETB, whereas the zona fasciculata/reticularis is exclusively provided with ETB. ET-1, ET-3 and BQ-3020 enhance aldosterone and corticosterone secretion by dispersed cells of the zona glomerulosa and zona fasciculata/reticularis, respectively. BQ-123 does not affect the secretagogue action of these three agonists, whereas BQ-788 completely annuls it. ET-1 induces a marked rise in catecholamine release by fragments of the adrenal medulla, and both BQ-123 and BQ-788 partially reverse this effect. ET-3 and BQ-3020 elicit a catecholamine release that is less intense than that produced by ET-1; this response is unaffected by BQ-123 and abolished by BQ-788. Thus, in the rat, the corticosteroid secretagogue effect of ETs seems to be exclusively mediated by the ETB receptor subtype, and the catecholamine secretagogue action by both ETA and ETB. The functional relevance of ETA receptors present in the zona glomerulosa remains to be investigated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050820
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Effects of ACTH and 3′,5′-cyclic purine nucleotides on the morphology and metabolism of normal adult human adrenocortical cells in primary tissue culture (1978)
    Springer
    Cell & tissue research 190 (1978), S. 187-205 
    Details
    ISSN: 1432-0878
    Keywords: Human adrenal cortex ; Cyclic-AMP ; Cyclic-GMP ; Steroidogenesis ; Stereology, electron microscopy, cell culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Stereological studies showed that treatment of normal adult human adrenocortical cells in primary culture with ACTH or cyclic-AMP for 2 days results in similar increases in the volume of cells, of the mitochondrial and “membrane space” compartments and of the surface area of the smooth endoplasmic reticulum and mitochondrial cristae, and decrease in the lipid content of the cells. These changes were more marked after 8 days of treatment. Treatment for 2 days with cyclic-GMP had no striking effects on cell ultrastructure, whereas an 8-day treatment led to ultrastructural changes similar to those obtained after 2 days of ACTH-or cyclic-AMP-treatment. A discrete population of untreated cortical cells maintained a slow proliferation that was not effected by exposure to cyclic-GMP, but was significantly increased in cultures treated with ACTH or cyclic-AMP. Radioimmunological studies showed that untreated cortical cells kept secreting progesterone and cortisol and that ACTH, but neither cyclic nucleotide, increased the secretion rate per cell of both hormones. These results assign a major role to cyclic-AMP and a minor one to cyclic-GMP in the mediation of the differentiation-promoting and trophic effects, but not in the steroidogenic effects of ACTH on the human adrenal cortex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00218169
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Cyclic AMP induces ultrastructural differentiation of normal adult human adrenocortical cells cultured in vitro (1975)
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 142 (1975), S. 533-538 
    Details
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Electron microscopic studies have revealed that cyclic AMP, like ACTH, induces structural differentiation of adult human adrenocortical cells cultured in vitro. These findings support the hypothesis that cyclic AMP can function as an intracellular mediator of the action of ACTH on the human adrenal gland.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1001420411
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Stimulation by N6,O2′-dibutyryl adenosine 3′,5′-cyclic monophosphate of RNA and DNA synthesis and of cell proliferation of rat hepatocytes in primary tissue cultureAbbreviations used: ASA, apparent surface area; cAMP, adenosine 3′,5′-cyclic monophosphate; CMI%, per cent colchicine metaphase index; DBcAMP, N6,O2′-dibutyryl adenosine 3′,5′-cyclic monophosphate; cGMP, guanosine 3′,5′-cyclic monophosphate; LI, labelling index; (Me-3H)Tdr, thymidine-methyl-3H; MI, mitotic index; U, (5-3H)uridine; URC, (5-3H)uridine radioactivity concentration per 100μ2; 5′-AMP, adenosine 5′-phosphate; MBcAMP, N6- or O2′-monobutyryl cAMP. (1976)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 89 (1976), S. 157-170 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The effects of DBcAMP in doses from 1.5 × 10-8 to 1.5 × 10-3 M on the compartmental apparent surface area (ASA) and (5-3H)uridine radioactivity concentration (URC), (methyl-3H)thymidine labelling index per 1 hour ([Me-3H]Tdr LI/h) and per cent mitotic index (MI%) and colchicine metaphase index (CMI%) of young rat differentiated hepatocytes in primary tissue culture were investigated by morphometric and radioautographic methods. In these cells DBcAMP was found to elicit: (1) progressive increments in the ASA of nucleoli, karyoplasm and cytoplasm; (2) peak increases in nucleolar URC at 1.5 × 10-8 and 10-5 M, but a slight decrease at 1.5 × 10-3 M; (3) significant increments in karyoplasmic and total nuclear URC at all doses, except at 1.5 × 10-6 and 10-4 M, when such parameters remained at control levels; (4) steady and progressive increases in cytoplasmic and total cell URC values; (5) marked increments in (Me-3H)Tdr LI/h, MI% and CMI% up to the dose of 1.5 × 10-4 M, but at 1.5 × 10-3 M these parameters were found to be either much less enhanced or to approach closely to control values.cAMP in doses from 1.5 × 10-8 to 10-4 M also markedly incremented the in vitro hepatocyte CMI%, while having a lesser stimulatory effect at 1.5 × 10-3 M.Finally of the various possible metabolites of DBcAMP administered at 1.5 × 10-8 M to liver cultures, N6- and O2′-MBcAMP and, again, cAMP significantly increased the CMI% of cultured hepatocytes, whereas 5′-AMP, adenosine and allantoin had no significant effect and Na-butyrate slightly decreased it.The present observations strengthen the hypothesis that cAMP and its butyrated derivatives, by possibly amplifying the template activity of the liver chromatin, accelerate the flow of differentiated primary young rat hepatocytes into the various stages of the mitotic cell cycle.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1040890115
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...