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Publication
Journal: Clinical Endocrinology
February/8/2006
Abstract
All endocrinologists would like to make glucocorticoid replacement therapy for their hypoadrenal patients as physiological as possible. Many would like the reassurance of a method of monitoring such treatment to confirm that they are achieving this aim. Advances in our knowledge of the normal physiology are relevant to our attempts to do this. The cortisol production rate in normal subjects is lower than was previously believed. The normal pattern of glucocorticoid secretion includes both a diurnal rhythm and a pulsatile ultradian rhythm. Glucocorticoid access to nuclear receptors is 'gated' by the 11-beta-hydroxysteroid dehydrogenase enzymes, which interconvert active cortisol and inactive cortisone. Such complexities make the target of physiological glucocorticoid replacement therapy hard to achieve. The available evidence suggests that conventional treatment of hypoadrenal patients may result in adverse effects on some surrogate markers of disease risk, such as a lower bone mineral density than age-sex matched controls, and increases in postprandial glucose and insulin concentrations. Although the quality of life of hypoadrenal patients may be impaired, there is no evidence of an improvement on higher doses of steroids, although quality of life is better if the hydrocortisone dose is split up, with the highest dose taken in the morning. Thus the evidence suggests that most patients may safely be treated with a low dose of glucocorticoid (e.g. 15 mg hydrocortisone daily) in two or three divided doses, with education about the appropriate action to take in the event of intercurrent illnesses.
Publication
Journal: Clinical Pharmacology and Therapeutics
December/17/1982
Abstract
To investigate the effect of glucocorticoids on beta-agonist-induced desensitization, we studied the effect of a single intravenous dose of methylprednisolone (2 mg/kg) on beta-receptor density and affinity in lymphocytes from four normal and four mildly asthmatic subjects at the end of 3 to 5 wk of terbutaline therapy and from four normal subjects taking no other drug. Terbutaline decreased (-)[3H]-dihydroalprenolol binding sites by 53% in normal and by 42% in asthmatic subjects. Methylprednisolone restored the number of binding sites to levels statistically indistinguishable from the preterbutaline values in both groups of subjects. In subjects not exposed to terbutaline beforehand there was no significant alteration in receptor density after methylprednisolone, nor in normal lymphocytes incubated in vitro for 90 min with hydrocortisone (10(-5)M). No significant change in the dissociation constant was observed in any situation. A single intravenous dose of methylprednisolone reverses terbutaline-induced down-regulation of beta-adrenoceptors. This may provide a mechanism for the beneficial effect of steroids in restoring catecholamine responsiveness in asthmatic subjects.
Publication
Journal: Journal of Clinical Investigation
March/23/1981
Abstract
The activity of prolylcarboxypeptidase (PCP), or angiotensinase C, was measured in lung tissues, leukocytes, and cultured human cells using Cbz-Pro-[14C]Ala as a substrate. A lysosomal fraction of homogenized rat or human lung contained most of the PCP activity in that tissue. Polymorphonuclear neutrophils, macrophages, and lymphocytes isolated from human blood had PCP activity. Fibroblasts cultured from human tissues had the highest activity (0.56-1.15 mumol/h per 10(6) cells), more than endothelial cells cultured from human pulmonary arteries. PCP of cultured human fibroblasts was similar to the human renal enzyme because it was resistant to moderate heating and was not inhibited by p-chloromercuriphenyl sulfonic acid. These properties and the substrate specificity distinguish PCP from cathepsin A, which is also in fibroblasts. Antibody to human renal PCP reacted with fibroblast PCP in immunofluorescence, indicating common antigenic determinants. Hydrocortisone changed PCP activity in fibroblasts in parallel with changes in beta-glucuronidase activity and cell-protein concentration; the activity was depressed at low concentration of the hormone. PCP activity was also found in synovial fluid from arthritic joints and in fibroblasts from the synovium. That PCP is found in both inflammatory exudates and in cells that appear at sites of inflammation indicates that, in addition to inactivating angiotensins, this enzyme may have a role in inflammation.
Publication
Journal: The Lancet
June/30/2000
Publication
Journal: The Lancet
May/30/1990
Abstract
The enzyme 11 beta-hydroxysteroid dehydrogenase (11 beta-OHSD), which catalyses the conversion of cortisol to the inactive steroid cortisone in man (and corticosterone to 11-dehydrocorticosterone in rodents), was demonstrated by immunohistochemistry in skin biopsy samples from healthy volunteers and from patients with psoriasis and eczema. In-vitro studies confirmed the presence of the enzyme in skin from nude mice and showed that it is inhibited by glycyrrhetinic acid, the major active component of liquorice. By means of the skin vasoconstrictor assay, glycyrrhetinic acid was shown to potentiate the action of hydrocortisone. This work suggests a novel means of targeting glucocorticoid therapy.
Publication
Journal: Annals of Surgery
June/16/1978
Abstract
The use of adrenalectomy and hypophysectomy in the management of postmenopausal patients with metastatic breast carcinoma is reserved for highly selected patients. As an alternate approach, a pharmacologic method of inhibiting adrenal cortical secretion was developed which consisted of the daily administration of 1000 mg of aminoglutethimide to block steroidogensis and either dexamethasone (2.0-3.0 mg/day) or hydrocortisone (40-60 mg/day) as replacement glucocorticoid. This regimen markedly suppressed plasma levels of DHA-S, androstenedione, estrone, and estradiol, and urinary levels of aldosterone. Of 50 patients treated, 19 (38%) demonstrated either a complete (8/19) or a partial (11/19) objective disease remission which lasted for 18.05 +/- 3.1 months (mean +/- SEM). In 10 (20%) patients, there was stabilization of disease (7.8 +/- 1.2 months), accompanied by symptomatic relief of bone pain in six (12%). There was disease progression in 20 (40%) patients. The acute side effects of aminoglutethimide therapy were significant and consisted of transient lethargy (41.5%) and a cutaneous rash (35.8%). Chronic toxicity was negligible. The medical adrenalectomy regimen of aminoglutethimide plus glucocorticoid offers a suitable alternative to surgical adrenalectomy or hypophysectomy in the management of postmenopausal patients with metastatic breast carcinoma.
Publication
Journal: Toxicological Sciences
April/9/2008
Abstract
Teratogenic effects are observed following long-term administration of glucocorticoids, although short-term glucocorticoid therapy is still utilized to reduce fetal mortality, respiratory distress syndrome, and intraventricular hemorrhage in preterm infants. However, the mechanism of glucocorticoid-induced teratogenicity is unknown. We hypothesize that glucocorticoid-induced teratogenesis is mediated through the glucocorticoid receptor (GR) and results from altering the expression and activity of the matrix metalloproteinases (MMPs). During embryogenesis, degradation of the extracellular matrix to allow for proper cellular migration and tissue organization is a tightly regulated process requiring appropriate temporal and spatial expression and activity of the MMPs. Studies have demonstrated that MMP gene expression can be either inhibited or induced by glucocorticoids in a variety of model systems. Using the zebrafish (Danio rerio) as a model of development, the data presented here demonstrate that embryonic exposure to the glucocorticoids dexamethasone or hydrocortisone increased expression of two gelatinases, MMP-2 ( approximately 1.5-fold) and MMP-9 (7.6- to 9.0-fold), at 72 h postfertilization (hpf). Further, gelatinase activity was increased approximately threefold at 72 hpf following glucocorticoid treatment, and changes in craniofacial morphogenesis were also observed. Cotreatment of zebrafish embryos with each glucocorticoid and the GR antagonist RU486 resulted in attenuation of glucocorticoid-induced increases in MMP expression (52-84% decrease) and activity (41-94% decrease). Furthermore, the abnormal craniofacial phenotype observed following glucocorticoid exposure was less severe following RU486 cotreatment. These studies demonstrate that in the embryonic zebrafish, dexamethasone, and hydrocortisone alter expression and activity of MMP-2 and -9, and suggest that these increases may be mediated through the GR.
Publication
Journal: British Journal of Pharmacology
October/4/1973
Abstract
Infusion of hydrocortisone in man caused an immediate shortening of the plasma half-life of antipyrine. There was no change in the 'apparent' volume of distribution of antipyrine and the plasma concentrations of hydrocortisone during the infusion remained within physiological limits. Similar changes in plasma half-lives of antipyrine were observed in the dog, but in vitro studies of drug oxidation with dog liver failed to show any difference between biopsy samples taken before and during steroid infusion.Many drugs and chemicals are known to stimulate rates of drug oxidation in both man and animals. Administration of these inducing agents results in an increase in the activity of enzymes catalyzing drug oxidation, most of which are located with-in the endoplasmic reticulum of liver cells. In man there is usually a delay of 4-8 days before an appreciable change in rates of drug metabolism is seen when such an agent is administered (Breckenridge, Orme, Thorgeirsson, Davies & Brooks, 1971); in rats, the administration of enzyme-inducing agents causes increased rates of drug metabolism only 24-48 h after their administration.We wish to report in this paper an immediate and hitherto undescribed effect of hydrocortisone on rates of antipyrine elimination in man.
Publication
Journal: Best practice & research. Clinical endocrinology & metabolism
August/18/2009
Abstract
Classical congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency leads to glucocorticoid and mineralocorticoid deficiency. Management should be viewed as a process of care which requires input from an interdisciplinary team. Glucocorticoid therapy should take the form of hydrocortisone in a starting dose of 15 mg/m(2)/day (divided into three doses), and the dose should be titrated to blood or urine profiles of cortisol and 17-hydroxyprogesterone. Mineralocorticoid replacement (9 alpha-fludrocortisone) requires higher doses in infancy and childhood than in adolescence. The starting dose should be 150 microg/m(2)/day, and the dose thereafter titrated to plasma renin activity and blood pressure. Despite adequate glucocorticoid substitution and concordance with medical therapy, control can be difficult during puberty due to alterations in the clearance of hydrocortisone, and dosing schedules may need to be adjusted to account for this. Follow-up should address the many facets of CAH, which should be assessed at an annual review, and a suggested protocol is presented.
Publication
Journal: Proceedings of the National Academy of Sciences of the United States of America
February/8/1971
Abstract
Glycerol-3-phosphate dehydrogenase (EC 1.1.1.8) is induced when glial cells are exposed to hydrocortisone in vitro. In contrast, the enzyme activity in fibroblasts is not affected by the steroid. In an attempt to elucidate the mechanisms controlling inducibility, hybrids between glial cells and fibroblasts were studied. It was found that the activity of the enzyme does not increase when the hybrids are exposed to hydrocortisone. It was also shown that inducibility and the noninduced activity of enzyme are controlled independently. Comparisons of S-100 and glycerol phosphate dehydrogenase activity in the hybrids suggest that all the specialized functions characteristics of glial cells are not coordinately controlled.
Publication
Journal: Journal of Infectious Diseases
October/9/1985
Abstract
Cytolysis of target cells by Entamoeba histolytica is a rapid, contact-dependent event that appears to involve calcium and amebic phospholipase A enzymes. There are two phospholipase A enzymes of E. histolytica: one calcium independent and optimally active at an acid pH, and a second calcium dependent and most active at an alkaline pH. The amebic calcium-dependent enzyme was inhibited by pharmacological antagonists that have been shown to reduce cytolysis of target cells by intact amebae: phosphatidylcholine (10(-3) M), Rosenthal's inhibitor (dimethyl-dl-2,3-distearoylpropyl-2'-hydroxyethyl ammonium acetate; 10(-4) M), quinacrine (10(-4) M), and hydrocortisone (10(-4) M). Calcium-independent phospholipase A activity was inhibited by Rosenthal's inhibitor (10(-4) M) and quinacrine (10(-3) M). The calcium-dependent phospholipase A enzyme is highly associated with plasma membrane fractions; the calcium-independent enzyme is predominantly found in soluble fractions. These findings further suggest an association of calcium-dependent phospholipase A activity with cytolytic activity of E. histolytica.
Publication
Journal: Hypertension
March/2/1995
Abstract
Increasing evidence has accumulated for rapid nongenomic steroid actions in various cell systems and, more recently, for rapid aldosterone effects on the Na(+)-H+ antiport in human mononuclear leukocytes. The aim of the present study was to demonstrate a rapid, nongenomic aldosterone action in rat vascular smooth muscle cells as a key effector cell in cardiovascular regulation. Basal 22Na+ influx in quiescent vascular smooth muscle cells was 22.1 +/- 1.9 nmol/mg protein per minute (mean +/- SEM, n = 9). Aldosterone (1 nmol/L) stimulated influx to 28.6 +/- 1.5 nmol/mg protein per minute after 4 minutes (n = 9, P < .05), with a half-maximal effect between 0.1 and 0.5 nmol/L; the effects were inhibited by ethylisopropylamiloride, the specific inhibitor of the Na(+)-H+ exchanger, demonstrating the involvement of this transport system in rapid effects of aldosterone. Hydrocortisone (1 mumol/L) was ineffective, and fludrocortisone and deoxycorticosterone increased influx with half-maximal effects at approximately 0.5 nmol/L. Canrenone, a classic antagonist of aldosterone action, did not inhibit stimulation by aldosterone at a 1000-fold excess concentration. Aldosterone significantly stimulated intracellular inositol 1,4,5-trisphosphate levels (P < .05) after 30 seconds; the inhibitors of phospholipase C, neomycin and U-73122, inhibited aldosterone-stimulated Na+ influx and increase of intracellular inositol 1,4,5-trisphosphate. The rapid stimulation of sodium transport in vascular smooth muscle cells and the pharmacological characteristics of this effect are clearly incompatible with the classic, genomic pathway of steroid action and represent further evidence for nongenomic effects of aldosterone.
Publication
Journal: Biochimica et Biophysica Acta - General Subjects
December/12/1967
Publication
Journal: Biochemical Journal
April/9/1968
Abstract
Hydrocortisone has been found to induce glutamine synthetase activity in chick-embryo retinas in culture. Evidence is presented to show that the hydrocortisone is definitely required for transcription; its requirement for translation has not been ruled out. The possible identity of hydrocortisone with an active component of calf-serum diffusate reported earlier is discussed. The data also indicate that the glutamine synthetase messenger RNA is stable for at least several hours.
Publication
Journal: International Journal of Cancer
April/22/1980
Abstract
Diploid cells derived from the portio surface of the cervix uteri of adult women can be grown in culture, from single cells. Ultrastructurally the colonies of growing cells show the features of stratified squamous epithelium and exhibit some of the differentiated characteristics of this epithelium in vivo. The successful serial cultivation of cervical epithelial cells, HCE, depends upon the presence of a non-dividing fibroblast feeder layer which provides both attachment and growth factors for epithelial cells. Lethally irradiated Wi-38, cervical fibroblasts or mouse fibroblast lines are all effective in promoting HCE colony formation and growth. Hydrocortisone and epidermal growth factor increase HCE colony size in the presence of a feeder cell layer. Culture lifetime was studied in five strains and ranged from 20-38 population doublings, with cells from older patients exhibiting a shorter culture life-time.
Publication
Journal: Annals of Neurology
September/24/1992
Abstract
An increased density of beta-adrenergic receptors was demonstrated on peripheral blood mononuclear cells (PBMCs) from patients with progressive or relapsing-remitting multiple sclerosis (MS). The same observation was made in patients with chronic active rheumatoid arthritis, but not in those with myasthenia gravis. The affinity of the receptors was within the normal range in all tested groups of patients and there was a positive correlation between density and function as determined by intracellular cyclic AMP production after stimulation with isoproterenol. A putative link between inflammatory process and the functional upregulation of beta-adrenergic receptors on PBMCs was tested by in vitro studies with the soluble mediators interleukin-1 and hydrocortisone. A functional upregulation of beta-adrenergic receptors was observed when PBMCs from normal control subjects were cultured in the presence of either mediator, whereas the already upregulated receptor density on PBMCs from patients with MS remained unchanged. Whether this represents a recovery mechanism to inflammation in MS or a blunting of homeostatic immunoregulatory mechanisms requires further investigation.
Publication
Journal: British Journal of Pharmacology
April/14/1977
Abstract
1 Rabbit isolated peritoneal neutrophil polymorphonuclear leucocytes were depleted of calcium by exposure for 1 h to calcium-free bathing fluid at 4 degrees C. 2 Addition of calcium ions to the previously calcium-depleted calls during incubation at 37 degrees C stimulated the release of beta-glucuronidase and of lysozyme but not of lactate dehydrogenase. 3 Low concentrations of indomethacin, flufenamate or salicylate, such as those which occur in the blood plasma after therapeutic doses of these drugs, selectively inhibited the calcium-induced release of beta-glucuronidase. The slight release of this enzyme which occurred in the absence of added calcium ions was not altered by these drugs, neither was the release of lactate dehydrogenase. 4 Release of lysozyme was inhibited by low concentrations of salicylate, amidopyrine or oxyphenbutazone, independent of the presence or absence of calcium ions. 5 Chloroquine, hydrocortisone or colchicine did not alter the release of leucocyte enzymes.
Publication
Journal: Journal of Clinical Investigation
July/8/1973
Abstract
On the basis of serial studies the responsiveness of leukocytes and lymphocytes from asthmatic donors to catecholamines was increased during high dose corticosteroid therapy. Similar changes were observed in the cells of normal control subjects given 200 mg of hydrocortisone intravenously. The increase in responsiveness did not appear to be due to changes in lymphocyte subpopulations although this may be a contributing factor. In an effort to elucidate the basis for the improved response, in vitro effects of glucocorticoids on lymphocyte cyclic AMP concentrations were investigated. Glucocorticoids (prednisolone succinate, hydrocortisone, hydrocortisone phosphate, and hydrocortisone succinate) stimulated cyclic AMP accumulation in asthma and normal control lymphocytes, increases occurring within the first 2 min of incubation. In the absence of theophylline, responses were regularly obtained at 10 muM hydrocortisone and usually at 1 muM hydrocortisone but not at submicromolar steroid concentrations. Theophylline potentiated the cyclic AMP response to glucocorticoids and also increased the percentage of positive responses in the 0.01-1.0 muM corticosteroid range. Combinations of 1 muM hydrocortisone and 1 muM epinephrine were sometimes additive or synergistic but in many instances higher glucocorticoid concentrations were needed to obtain augmentation of the catecholamine response. The in vitro glucocorticoid effects may not fully explain their potentiating action in vivo.
Publication
Journal: Gastroenterology
August/10/1983
Abstract
Sixty-six patients hospitalized for ulcerative colitis were treated in a prospective, double-blind, clinical trial. They received either 120 U/day of intravenous corticotropin or 300 mg/day of intravenous hydrocortisone. Patients were randomized within strata defined by whether they had received oral corticosteroids continuously for at least 30 days before the study (group A, 35 patients), or whether they had received no such prior treatment (group B, 31 patients). Twenty-eight of the 66 patients (42%) achieved remission. In group B, the proportion of patients entering remission was greater with corticotropin than with hydrocortisone (63% vs. 27%, 0.025 less than p less than 0.05). The opposite trend was observed within group A, for whom hydrocortisone appeared more effective (53% vs. 25%, 0.05 less than p less than 0.10). Impaired adrenal responsiveness, as measured by serum cortisol and dehydroepiandosterone-sulfate levels, did not explain the different responses to therapy within the two study groups. Twenty of 28 patients whose acute therapy was successful were still in remission 1 yr after study. These data suggest that, at the doses used, intravenous corticotropin therapy of severe ulcerative colitis is the more effective choice for those patients not previously treated with corticosteroids, while intravenous hydrocortisone seems preferable for patients already receiving steroid treatment.
Publication
Journal: Naunyn-Schmiedeberg's Archives of Pharmacology
April/19/1982
Abstract
1. Hearts of cats and rabbits were perfused at a constant rate with 3H-(--)noradrenaline for 60-120 min. During the perfusion the rate of net removal of 3H-noradrenaline from the perfusion fluid and the rate of efflux of 3H-metabolites from the hearts were followed. From these results and from the amount of 3H-metabolites recovered from the hearts (at the end of experiments), the time course of the cumulative metabolite formation was obtained. The following metabolites were determined: 3,4-dihydroxyphenylethyleneglycol (DOPEG), 3,4-dihydroxymandelic acid (DOMA), normetanephrine (NMN) and a fraction consisting of 3-methoxy-4-hydroxyphenylethyleneglycol and 3-methoxy-4-hydroxymandelic acid (OMDA). 2. In normal hearts, the rate of formation of DOPEG, DOMA and OMDA became constant only after a considerable delay, and the rate of efflux of these metabolites did not reach a constant value within 120 min. By contrast, the formation of NMN proceeded at a constant rate throughout the perfusion with 3H-noradrenaline, and the rate of efflux of NMN approached a steady level within about 30 min. 3. In hearts of reserpine-pretreated animals not only NMN, but also DOPEG, DOMA and OMDA quickly approached a constant rate of formation. In addition, the efflux of all metabolites attained a steady level, and after about 70 min, the hearts of both species reached a steady state in which the net removal of 3H-noradrenaline was fully accounted for by the formation of metabolites. 4. The metabolite pattern during the steady state showed striking species differences. The rate of metabolite formation (expressed % of the steady-state rate of 3H-noradrenaline removal) decreased in the order DOPEG (40.0%) greater than NMN (30.8%) greater than DOMA (18.1%) greater than OMDA (9.0%) in the cat heart and DOPEG (66.8%) greater DOMA (20.0%) greater than OMDA (6.6%) greater than NMN (1.5%) in the rabbit. 5. In both species, 30 mumol . 1-1 cocaine (to inhibit neuronal uptake) decreased the rate of formation of DOPEG, DOMA and OMDA to very low values, but increased the formation of 3H-NMN. 6. In the cat heart, 30 mumol . 1-1 hydrocortisone (to inhibit extraneuronal uptake) decreased the formation of NMN, while having no effect on the formation of DOPEG, DOMA and OMDA. Moreover, in the cat and rabbit heart perfused in the presence of cocaine, inhibition of extraneuronal uptake markedly affected the formation of NMN. 7. A linear relationship was found for all metabolites between the rate of efflux and the tissue content (both parameters being determined during steady state), indicating first-order kinetics of efflux. The ranking order of the overall rate constants for efflux was DOPEG much greater than NMN greater than DOMA.
Authors
Publication
Journal: Biochemical Journal
September/16/1966
Abstract
1. The action of excess of retinol on chick limb-bone rudiments cultured in chemically defined media has been investigated. 2. After 6 days in vitro, the hexosamine and hydroxyproline contents of the retinol-treated rudiments were much less than those of their paired controls. 3. Synthesis of these compounds, however, was not correspondingly decreased. 4. The control rudiments released hexosamine- and hydroxyproline-containing materials into the culture medium; a greater proportion of the hexosamine and hydroxyproline synthesized was liberated from the retinol-treated than from the control rudiments. 5. Although hydrocortisone in physiological concentrations prevented excessive hydration of the rudiments in culture, it did not significantly inhibit the changes induced by excess of retinol.
Publication
Journal: Journal of Clinical Oncology
August/28/1989
Abstract
High-dose ketoconazole (400 mg orally three times a day) and physiologic replacement doses of glucocorticoids (hydrocortisone, 20 mg 8 AM, 10 mg 4 PM, and 8 PM) were administered to 38 patients with advanced prostatic cancer, refractory to at least initial testicular androgen deprivation. Thirty patients were completely evaluable; six were withdrawn due to possible ketoconazole-related toxicity and were considered drug failures. Two patients were unevaluable due to intercurrent therapy or inability to maintain follow-up. Ketoconazole was generally well tolerated. Mild or moderate nausea and vomiting occurred in 37% of patients, but required dose modification or discontinuation in only three patients; no hepatic damage was seen. Five of 36 patients (14%) responded to ketoconazole as determined by palpable or radiographic tumor mass reduction of 50% or greater and normalization of acid phosphatase or bone scan. Fifty percent of patients entered were stable at 90 days. Plasma androstenedione and dehydroepiandrosterone sulfate (DHEAS) were reduced markedly in almost all patients. Plasma testosterone (T) levels were low and remained unchanged, while gonadotropins were persistently elevated. Mean plasma ketoconazole content was 6.6 micrograms/mL after 28 days of therapy. While ketoconazole with hydrocortisone does suppress plasma androgens in advanced prostatic cancer patients, this infrequently causes regression of cancer that has progressed despite adequate testicular androgen ablation.
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Publication
Journal: Biochemical and Biophysical Research Communications
June/21/1984
Abstract
Three acute-phase proteins, haptoglobin, alpha 2-macroglobulin and hemopexin, as well as albumin, have been measured daily in the hydrocortisone-supplemented serum-free medium of pure and mixed cultures of adult rat hepatocytes for 5 and 20 days respectively. Whereas plasma protein production rapidly declined in pure culture, it remained relatively stable when hepatocytes were co-cultured with rat liver epithelial cells. In the latter cultures, an early stimulation of albumin and alpha 2-macroglobulin secretion was observed. In addition, four other plasma proteins, fibrinogen, alpha 1-acute-phase protein, alpha 1-acid glycoprotein and alpha 1-antitrypsin were shown by immunodiffusion to still be produced by day 20 of co-culture. These results suggest that hepatocyte co-cultures represent a suitable model for studying the mechanism which controls synthesis of plasma proteins, including acute-phase proteins by liver cells.
Publication
Journal: British Journal of Haematology
June/22/1981
Abstract
Endothelial cells (ECs) derived from human umbilical veins were cultured in order to study the physiological control of factor VIII synthesis and release. The culture media were studied from multiple replicate cultures at confluence. Factor VIII related antigen (VIIIR:Ag) and factor VIII coagulant antigen (VIII:CAg) were measured by sensitive immunoradiometric assays. De novo synthesis of factor VIII related protein (VIII:R) was quantitated by incorporation of labelled amino acids into specific protein subunits. The following agents were added to the culture medium in a range of concentrations from physiological to pharmacological: adrenaline, 5 hydroxytryptamine, 2,3-DPG, cyclic AMP, thyroxine, hydrocortisone, and human growth hormone. None of them had any effect at any concentration on the rate of accumulation of VIIIR:Ag in the culture medium. Addition of exogenous factor VIII had no effect on do novo synthesis of VIII:R. VIII:CAg was found to be stable under the conditions of culture but none was released from the ECs. Long-term monocyte cultures also failed to release VIII:CAg. It appears that VIII:R is a constitutive gene product of umbilical vein endothelial cells and that VIII:CAg is not made by these cells.
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