Determination, Activation and Actinomycin D Insensitivity in the Optic Imaginal Disk of Drosophila

C. H. WADDINGTON; EVELYN ROBERTSON

doi:10.1038/221933a0

Effect of Some Metabolic Inhibitors on Vinblastine-Induced Ribosomal-Granular Material Complexes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100066796 ◽

1971 ◽

Vol 29 ◽

pp. 548-549

Author(s):

Awtar Krishan ◽

Dora Hsu

Keyword(s):

Granular Material ◽

Rna Synthesis ◽

Culture Medium ◽

Actinomycin D ◽

Metabolic Inhibitors ◽

Protein And Rna Synthesis ◽

Apparent Reduction ◽

Plant Alkaloids ◽

In Cells

Cells exposed to antitumor plant alkaloids, vinblastine and vincristine sulfate have large proteinacious crystals and complexes of ribosomes, helical polyribosomes and electron-dense granular material (ribosomal complexes) in their cytoplasm, Binding of H3-colchicine by the in vivo crystals shows that they contain microtubular proteins. Association of ribosomal complexes with the crystals suggests that these structures may be interrelated.In the present study cultured human leukemic lymphoblasts (CCRF-CEM), were incubated with protein and RNA-synthesis inhibitors, p. fluorophenylalanine, puromycin, cycloheximide or actinomycin-D before the addition of crystal-inducing doses of vinblastine to the culture medium. None of these compounds could completely prevent the formation of the ribosomal complexes or the crystals. However, in cells pre-incubated with puromycin, cycloheximide, or actinomycin-D, a reduction in the number and size of the ribosomal complexes was seen. Large helical polyribosomes were absent in the ribosomal complexes of cells treated with puromycin, while in cells exposed to cycloheximide, there was an apparent reduction in the number of ribosomes associated with the ribosomal complexes (Fig. 2).

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Failure of Actinomycin-D to Inhibit Passive Avoidance Learning: A Confirmation

PsycEXTRA Dataset ◽

10.1037/e469452008-062 ◽

1966 ◽

Author(s):

Thomas K. Landauer ◽

Lynn Eldridge

Keyword(s):

Passive Avoidance ◽

Avoidance Learning ◽

Actinomycin D ◽

Passive Avoidance Learning

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

Acta Endocrinologica ◽

10.1530/acta.0.057s019 ◽

1968 ◽

Vol 57 (3_Suppl) ◽

pp. S19-S35 ◽

Cited By ~ 9

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.

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CONTRIBUTION TO THE EXISTENCE OF REGULATORY MECHANISMS AT THE ADRENAL LEVEL

Acta Endocrinologica ◽

10.1530/acta.0.0700741 ◽

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.

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

Acta Endocrinologica ◽

10.1530/acta.0.0770064 ◽

1974 ◽

Vol 77 (1) ◽

pp. 64-70 ◽

Cited By ~ 9

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.

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