Inhibition of macrophage aggregation in vitro by actinomycin D and puromycin

1971 ◽  
Vol 2 (5) ◽  
pp. 386-398 ◽  
Author(s):  
Somsak Lolekha ◽  
Samuel P. Gotoff
Keyword(s):  
Actinomycin D ◽  
Macrophage Aggregation

ANALYSIS OF THE BIPHASIC ACTION OF GROWTH HORMONE IN VITRO ON THE RAT DIAPHRAGM

1968 ◽  
Vol 57 (3_Suppl) ◽  
pp. S19-S35 ◽  
Author(s):  
Å. Hjalmarson
Keyword(s):  
Growth Hormone ◽  
Actinomycin D ◽  
Accumulation Rate ◽  
Inhibitory Effect ◽  
Bovine Growth Hormone ◽  
Rat Diaphragm ◽  
Dual Nature ◽  
Hypophysectomized Rats ◽  
D 20

ABSTRACT In vitro addition of bovine growth hormone (GH) to intact hemidiaphragms from hypophysectomized rats has previously been found to produce both an early stimulatory effect lasting for 2—3 hours and a subsequent late inhibitory effect during which the muscle is insensitive to further addition of GH (Hjalmarson 1968). These effects on the accumulation rate of α-aminoisobutyric acid (AIB) and D-xylose have been further studied. In presence of actinomycin D (20 μg/ml) or puromycin (100 μg/ml) the duration of the stimulatory effect of GH (25 μg/ml) was prolonged to last for at least 4—5 hours and the late inhibitory effect was prevented. Similar results were obtained when glucose-free incubation medium was used. Preincubation of the diaphragm at different glucose concentrations (0—5 mg/ml) for 3 hours did not change the GH sensitivity. Addition of insulin at start of incubation could not prevent GH from inducing its late inhibitory effect, while dexamethasone seemed to potentiate this effect of GH. Furthermore, adrenaline was found to decrease the uptake of AIB-14C and D-xylose-14C in the diaphragm, but not to change the sensitivity of the muscle to GH. Preincubation of the diaphragm for 3 hours with puromycin in a concentration of 200 μg/ml markedly decreased the subsequent basal uptake of both AIB-14C and D-xylose-14C, in the presence of puromycin, and abolished the stimulatory effect of GH on the accumulation of AIB-14C. However, the effect of GH on the accumulation of D-xylose-14C was unchanged. The present observations are discussed and evaluated in relation to various mechanisms of GH action proposed to explain the dual nature of the hormone.

CONTRIBUTION TO THE EXISTENCE OF REGULATORY MECHANISMS AT THE ADRENAL LEVEL

1972 ◽  
Vol 70 (4) ◽  
pp. 741-757
Author(s):  
Otto Linèt
Keyword(s):  
Orotic Acid ◽  
Adrenal Glands ◽  
Actinomycin D ◽  
Delay Period ◽  
Regulatory Mechanisms ◽  
Leucine Incorporation ◽  
Total Period ◽  
Free Media

ABSTRACT Rat adrenal glands atrophied by the administration of cortisol acetate in vivo were used as a model for the study of early metabolic processes occurring in vitro. Atrophied adrenals incubated in the presence of 14C-leucine incorporated subnormal quantities of this amino acid per mg of protein for the first 120 min. When the incubation lasted for a total period of 180 or 240 min a supranormal rise in the 14C-leucine incorporation was observed. Similar changes occurred with some delay with regard to corticosterone production as expressed per 100 mg of tissue. No differences in 14C-leucine incorporation were observed between the control and atrophied adrenals in vivo. Homogenates from atrophied glands incorporated 14C-leucine to a greater extent than the control homogenates. The in vitro incorporation of 14C-orotic acid into the RNA was also higher in atrophied adrenals. The in vitro use of actinomycin D, cycloheximide and amphenone indicated that corticosterone production depended on the incorporation of 14C-leucine. The addition of cortisol to the incubation media markedly decreased the enhancement of 14C-lysine incorporation into the protein of atrophied adrenals. These, as well as additional results suggest rebound phenomena: once atrophic adrenals are transferred to cortisol-free media, reparative processes begin after a delay period. Such phenomena seem to be mediated by regulatory mechanisms at the adrenal level.

EFFECT OF ACTINOMYCIN D ON TSH-INDUCED STIMULATION OF THYROIDAL PROTEIN SYNTHESIS IN THE RAT

1974 ◽  
Vol 77 (1) ◽  
pp. 64-70 ◽  
Author(s):  
Gustav Wägar
Keyword(s):  
Protein Synthesis ◽  
Actinomycin D ◽  
The Other ◽  
Leucine Incorporation ◽  
Short Term ◽  
Other Hand ◽  
Thyroid Glands ◽  
Translational Level ◽  
Stimulation Of

ABSTRACT Whether the short-term regulation of thyroidal protein synthesis by TSH occurs at the transcriptional or the translational level was tested by measuring the effect of actinomycin D (act D) on the TSH-induced stimulation of L-14C-leucine incorporation into the thyroidal proteins of rats. TSH was injected 6 h before the rats were killed. The thyroid glands were then removed and incubated in vitro in the presence of L-14C-leucine for 2 h. The pronounced stimulation of leucine incorporation in the TSH-treated animals was depressed as compared with controls but still significant even when the animals had been pre-treated with 100 μg act D 24 and 7 h before sacrifice. On the other hand, act D strongly decreased incorporation of 3H-uridine into RNA. Short-term regulation of thyroidal protein synthesis by TSH appears to be partly but not wholly dependent on neosynthesis of RNA. Hence regulation may partly occur at the translation level of protein synthesis.

scholarly journals Identification and Functional Analysis of Apoptotic Protease Activating Factor-1 (Apaf-1) from Spodoptera litura

Insects ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 64
Author(s):  
Haihao Ma ◽  
Xiumei Yan ◽  
Lin Yan ◽  
Jingyan Zhao ◽  
Jiping Song ◽  
...  
Keyword(s):  
Spodoptera Litura ◽  
Actinomycin D ◽  
Titration Calorimetry ◽  
Apoptosis Pathway ◽  
Downstream Effector ◽  
Lepidopteran Insects ◽  
Evolutionarily Conserved ◽  
Effector Caspases ◽  
And Function

Apoptotic protease activating factor-1 (Apaf-1) is an adaptor molecule, essential for activating initiator caspase and downstream effector caspases, which directly cause apoptosis. In fruit flies, nematodes, and mammals, Apaf-1 has been extensively studied. However, the structure and function of Apaf-1 in Lepidoptera remain unclear. This study identified a novel Apaf-1 from Spodoptera litura, named Sl-Apaf-1. Sl-Apaf-1 contains three domains: a CARD domain, as well as NOD and WD motifs, and is very similar to mammalian Apaf-1. Interference of Sl-apaf-1 expression in SL-1 cells blocked apoptosis induced by actinomycin D. Overexpression of Sl-apaf-1 significantly enhances apoptosis induced by actinomycin D in Sf9/SL-1/U2OS cells, suggesting that the function of Sl-Apaf-1 is evolutionarily conserved. Furthermore, Sl-Apaf-1 could interact with Sl-caspase-5 (a homologue of mammalian caspase-9) and yielded a binding affinity of 1.37 × 106 M–1 according isothermal titration calorimetry assay. Initiator caspase (procaspase-5) of S. litura could be activated by Sl-Apaf-1 (without WD motif) in vitro, and the activated Sl-caspase-5 could cleave Sl-procaspase-1 (a homologue of caspase-3 in mammals), which directly caused apoptosis. This study demonstrates the key role of Sl-Apaf-1 in the apoptosis pathway, suggesting that the apoptosis pathway in Lepidopteran insects and mammals is conserved.

scholarly journals Biosynthesis of growth hormone in the rat anterior pituitary gland. Stimulation of biosynthesis in vitro by insulin

1973 ◽  
Vol 134 (4) ◽  
pp. 1103-1113 ◽  
Author(s):  
A. Betteridge ◽  
M. Wallis
Keyword(s):  
Growth Hormone ◽  
Anterior Pituitary ◽  
Rna Synthesis ◽  
Glucose Utilization ◽  
Actinomycin D ◽  
Hormone Synthesis ◽  
Pituitary Glands ◽  
Hormone Biosynthesis ◽  
Stimulation Of

The effect of insulin on the incorporation of radioactive leucine into growth hormone was investigated by using rat anterior pituitary glands incubated in vitro. A 50% stimulation over control values was observed at insulin concentrations above 2μm (280munits/ml). The effect was specific for growth hormone biosynthesis, over the range 1–5μm-insulin (140–700munits/ml). Lower more physiological concentrations had no significant effect in this system. Above 10μm (1.4 units/ml) total protein synthesis was also increased. The stimulation of growth hormone synthesis could be partially blocked by the addition of actinomycin D, suggesting that RNA synthesis was involved. Insulin was found to stimulate the rate of glucose utilization in a similar way to growth hormone synthesis. 2-Deoxyglucose and phloridzin, which both prevented insulin from stimulating glucose utilization, also prevented the effect of insulin on growth hormone synthesis. If glucose was replaced by fructose in the medium, the effect of insulin on growth hormone synthesis was decreased. We conclude that the rate of utilization of glucose may be an important step in mediating the effect of insulin on growth hormone synthesis.

scholarly journals The effects of salicylate on the activity of rat liver tyrosine–2-oxoglutarate aminotransferase in vitro and in vivo

1972 ◽  
Vol 126 (2) ◽  
pp. 347-350 ◽  
Author(s):  
A. A.-B. Badawy
Keyword(s):  
Rat Liver ◽  
Pyridoxal Phosphate ◽  
Actinomycin D ◽  
Sodium Salicylate ◽  
Intraperitoneal Administration ◽  
Tyrosine Aminotransferase ◽  
Major Effect ◽  
Endogenous Activity

1. Salicylate, in concentrations of 0.25mm and above, enhances the basal activity of tyrosine–2-oxoglutarate aminotransferase in homogenates of rat liver incubated in the absence of added pyridoxal 5′-phosphate (endogenous activity). The effect is decreased by increasing the concentration of the cofactor. 2. The intraperitoneal administration of sodium salicylate enhances the activity of rat liver tyrosine aminotransferase; the major effect during the first hour being on the enzyme in the absence of added pyridoxal phosphate. Actinomycin D prevents the induction of the enzyme by cortisol and tryptophan. Induction by pyridoxine or salicylate is 50% inhibited by actinomycin D. The effects of the injections of various combinations of cortisol, pyridoxine and salicylate were also studied in the absence or presence of actinomycin D. 3. It is suggested that salicylate induces rat liver tyrosine aminotransferase by displacing its protein-bound cofactor and that a cofactor-type induction of the hepatic enzyme occurs in pyridoxine-treated rats.

Early glucocorticoid feedback in anterior pituitary corticotrophs: differential inhibition of hormone release induced by vasopressin and corticotrophin-releasing factor in vitro

1991 ◽  
Vol 129 (2) ◽  
pp. 261-268 ◽  
Author(s):  
M. J. Shipston ◽  
F. A. Antoni
Keyword(s):  
Anterior Pituitary ◽  
Actinomycin D ◽  
Feedback Inhibition ◽  
Female Rats ◽  
Hormone Release ◽  
Type Ii ◽  
Acth Secretion ◽  
Corticotrophin Releasing Factor ◽  
Acth Release

ABSTRACT Vasopressin and 41-residue corticotrophin-releasing factor (CRF-41) are physiological mediators of the hypothalamic control of pituitary ACTH secretion, whilst adrenocortical glucocorticoids are the major inhibitory factors regulating ACTH output. In the present study it was investigated in vitro whether the characteristics of early glucocorticoid inhibition of stimulated ACTH secretion would differ depending on the nature of the stimulus and the temporal relationship between secretagogue and steroid. The experiments were carried out using perifused segments of rat adenohypophysis obtained from randomly cycling female rats. Repeated pulses (5 min) of CRF-41 or vasopressin were given at 1-h intervals for up to 7 h. The net release of ACTH became stable after the second secretagogue pulse. Administration of 0·1 μmol corticosterone/l 30 min before and during a 5-min pulse of 10 nmol CRF-41/l inhibited CRF-41-stimulated ACTH release to 60% of control. Stimulated hormone release remained suppressed at 90 min after the start of the corticosterone infusion and returned to control levels by 150 min. If corticosterone treatment (35 min total exposure) was started simultaneously with the CRF-41 pulse, no inhibitory effect of the steroid was observed at any subsequent time-point examined (60,90,120 and 150 min). In contrast, vasopressin-stimulated ACTH release was inhibited by approximately 50% when corticosterone was applied before, or simultaneously with, a 5-min pulse of 10 nmol vasopressin/l. The synthetic glucocorticoid type II receptor agonist RU28362, administered 30 min before and during a 5-min pulse of 10 nmol CRF-41/l, reduced CRF-41-stimulated ACTH release to 50% of control up to 2·5 h after the start of RU28362 application (although inhibition after 35 min exposure was not statistically significant). Inhibition of ACTH release stimulated by 10 nmol vasopressin/l was observed within 35 min of steroid application and was maintained up to 2·5 h after the initial application of RU28362. The action of RU28362 on CRF-41-stimulated ACTH release was blocked by inhibitors of transcription (actinomycin D) and translation (puromycin); notably these drugs did not modify the ACTH response to CRF-41. In contrast, actinomycin D as well as puromycin reduced vasopressin-stimulated ACTH release. The data suggest that: (1) the timing of steroid application is important in determining the early glucocorticoid inhibition of CRF-41- but not vasopressin-stimulated ACTH secretion; (2) CRF-41 and vasopressin mobilize different pools of ACTH from the anterior pituitary gland; (3) type II glucocorticoid receptors and synthesis of new protein(s) are involved in the early inhibitory action of glucocorticoids; (4) depending on the timing and nature of the incident secretagogue, differential negative feedback inhibition of ACTH secretion may occur at the pituitary level in vivo. Journal of Endocrinology (1991) 129, 261–268

scholarly journals Investigating the Central Nervous System Disposition of Actinomycin D: Implementation and Evaluation of Cerebral Microdialysis and Brain Tissue Measurements Supported by UPLC-MS/MS Quantification

Pharmaceutics ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1498
Author(s):  
Julia Benzel ◽  
Gzona Bajraktari-Sylejmani ◽  
Philipp Uhl ◽  
Abigail Davis ◽  
Sreenath Nair ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Brain Tissue ◽  
Actinomycin D ◽  
Tissue Concentration ◽  
Cerebral Microdialysis ◽  
Tissue Homogenate ◽  
In Vitro Experiments ◽  
Plasma Ratio

Actinomycin D is a potent cytotoxic drug against pediatric (and other) tumors that is thought to barely cross the blood–brain barrier. To evaluate its potential applicability for the treatment of patients with central nervous system (CNS) tumors, we established a cerebral microdialysis model in freely moving mice and investigated its CNS disposition by quantifying actinomycin D in cerebral microdialysate, brain tissue homogenate, and plasma. For this purpose, we developed and validated an ultraperformance liquid chromatography–tandem mass spectrometry assay suitable for ultra-sensitive quantification of actinomycin D in the pertinent biological matrices in micro-samples of only 20 µL, with a lower limit of quantification of 0.05 ng/mL. In parallel, we confirmed actinomycin D as a substrate of P-glycoprotein (P-gp) in in vitro experiments. Two hours after intravenous administration of 0.5 mg/kg, actinomycin D reached total brain tissue concentrations of 4.1 ± 0.7 ng/g corresponding to a brain-to-plasma ratio of 0.18 ± 0.03, while it was not detectable in intracerebral microdialysate. This tissue concentration exceeds the concentrations of actinomycin D that have been shown to be effective in in vitro experiments. Elimination of the drug from brain tissue was substantially slower than from plasma, as shown in a brain-to-plasma ratio of approximately 0.53 after 22 h. Because actinomycin D reached potentially effective concentrations in brain tissue in our experiments, the drug should be further investigated as a therapeutic agent in potentially susceptible CNS malignancies, such as ependymoma.

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