scholarly journals Differential effect of hormones on macromolecular synthesis and mitosis in chick embryo cells.

1975 ◽  
Vol 67 (2) ◽  
pp. 492-498 ◽  
Author(s):  
J B Baseman ◽  
N S Hayes
Keyword(s):  
Chick Embryo ◽  
Dna Synthesis ◽  
Metabolic Responses ◽  
Resting Cells ◽  
Cell Heterogeneity ◽  
Macromolecular Synthesis ◽  
Maximal Stimulation ◽  
Fresh Serum ◽  
Embryo Cells ◽  
Stimulation Of

Exposure of serum-deprived confluent monolayers of chick embryo cells to fresh serum results in maximal stimulation of synthesis of RNA and protein followed by increased DNA synthesis and mitosis. The addition of insulin to quiescent cultures effects a similar acceleration of synthesis of RNA and protein, but little stimulation of DNA synthesis and mitosis is evident. However, the simultaneous addition of insulin and hydrocortisone to resting cells causes a significant increase in the rate of DNA synthesis although the level reached is considerably lower than that obtained with serum and still no mitosis occurs. Unexpectedly, insulin plus hydrocortisone prevents maximal synthesis of RNA and protein in contrast to insulin-treated cultures. Nuclear autoradiography and percent mitosis of cells incubated with various regulatory factors indicate that cell heterogeneity exists and is reflected in the metabolic responses of subpopulations to specific regulatory signals.

scholarly journals Characterization of a photoproduct of 7,12-dimethylbenz[a]anthracene and its effects on chick-embryo cells in culture

1977 ◽  
Vol 164 (3) ◽  
pp. 481-486 ◽  
Author(s):  
D Warshawsky ◽  
E Kerns ◽  
M J Bissell ◽  
M Calvin
Keyword(s):  
Chick Embryo ◽  
Dna Synthesis ◽  
Oxidation Product ◽  
Biological Effects ◽  
Cell Number ◽  
Resonance Spectroscopy ◽  
Morphological Transformation ◽  
Morphological Alterations ◽  
Photo Oxidation ◽  
Embryo Cells

A common impurity of 7,12-dimethylbenz[alpha]anthracene was more effective than 7,12-dimethylbenz[alpha]anthracene in inducing morphological alterations, and in causing an increase in glucose uptake, DNA synthesis and cell number in chick-embryo fibroblasts. Gradual morphological transformation follows the increase in DNA synthesis after 2 days when either primary or secondary cultures are treated with 3 microgram of the compound/ml. The compound, isolated from 7,12-dimethylbenz[alpha]anthracene by alumina column chromatography, was characterized by t.l.c., mass spectroscopy, carbon-hydrogen analysis, u.v. and nuclear-magnetic-resonance spectroscopy and thermal decomposition. It was the photo-oxidation product of 7,12-dimethylbenz[alpha]anthracene, 7,12-epidioxy-7,12-dimethylbenz[alpha]anthracene. It is suggested that some of the biological effects observed after treatment of cultures with 7,12-dimethylbenz[alpha]anthracene may be due in part to the presence of the photo-oxidation product.

Late signals are required for the stimulation of DNA synthesis in rat mammary fibroblasts by growth factors

1996 ◽  
Vol 16 (3) ◽  
pp. 249-263 ◽  
Author(s):  
Hai-Lan Chen ◽  
Philip S. Rudland ◽  
John A. Smith ◽  
David G. Fernig
Keyword(s):  
Growth Factors ◽  
Growth Factor ◽  
Dna Synthesis ◽  
Maximal Response ◽  
High Concentration ◽  
Initial Concentration ◽  
Maximal Stimulation ◽  
Epidermal Growth ◽  
Lag Period ◽  
Stimulation Of

Maximal stimulation of DNA synthesis in quiescent rat mammary (Rama) 27 fibroblasts is elicited by epidermal growth factor (EGF) or basic fibroblast growth factor (bFGF) 18 h after the initial addition of the growth factors-the ‘lag’ period. At maximally-stimulating concentrations, EGF and bFGF are interchangeable 9 h after their initial addition. When the initial concentration of growth factor is below that required to elicit a maximal response, it is possible to increase the level of DNA synthesis by increasing the concentration of growth factor 9 h after its initial addition. When the initial concentration of growth factor is high, substitution by a lower concentration of growth factor after 9 h allows a greater proportion of cells to synthesize DNA than would be expected from a continuous low dose of growth factor. Similar results are obtained when both the growth factor and its concentration are changed 9 h after the initial addition of growth factor. However, when EGF at a low concentration is substituted for a high concentration of EGF or bFGF the resulting increase in the levels of DNA synthesis is greater when EGF rather than bFGF is added for a second time. The half-life of the growth-stimulatory signals delivered by EGF and by bFGF 9 h after their initial addition is 1–2 h. These results suggest that to stimulate DNA synthesis: (i) EGF or bFGF must deliver a signal(s) continuously; (ii) the initial signals produced by EGF and bFGF are equivalent; (iii) the signals produced between 9–18 h by EGF may be different to those produced by bFGF.

Growth Hormone-Dependent Serum Stimulation of DNA Synthesis in Chick Embryo Fibroblasts in Culture12

Endocrinology ◽  
1975 ◽  
Vol 96 (1) ◽  
pp. 193-198 ◽  
Author(s):  
KENNETH L. COHEN ◽  
PATRICIA A. SHORT ◽  
S. PETER NISSLEY
Keyword(s):  
Growth Hormone ◽  
Chick Embryo ◽  
Dna Synthesis ◽  
Serum Stimulation ◽  
Embryo Fibroblasts ◽  
Stimulation Of
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