The Newborn Mouse as a Model for Study of the Effects of Hormonal Steroids in the Young

PEDIATRICS ◽  
1978 ◽  
Vol 62 (6) ◽  
pp. 1143-1150
Author(s):  
Arthur F. Kohrman
Keyword(s):  
Rna Synthesis ◽  
Specific Binding ◽  
Model System ◽  
Tumor Formation ◽  
Newborn Mouse ◽  
Cervical Tumor ◽  
Newborn Period ◽  
Adult Mice ◽  
Protein And Rna Synthesis ◽  
Hormonal Steroids

The use of the fetal and neonatal mouse to study the effects of steroidal and nonsteroidal substances on development and carcinogenesis has a long history. Since the early 1960s, this animal model system has been exploited by several groups throughout the world, and it is useful to recount some of the more significant points in this history. I shall also point out areas of inquiry where the mouse model continues to be used in a search for the fundamental nature of the processes by which steroid hormones cause permanent effects during development, with the hope that some of those experiments may provide clues to the causes of present or yet unseen situations in the human. Early studies1,2 showed vaginal and cervical tumor formation in adult mice treated with estrogens in the newborn period. As early as 1963, concern was expressed about the possibility of similar consequences in humans who might be exposed to hormonal substances early in development. Subsequent investigations2-4 showed that administration of estrogen and androgen to newborn female mice in the first five days of life led to permanent vaginal and cervical changes in the adult, which were in many cases (depending on the dose administered) ovary independent; that is, the changes persisted after ovariectomy of the animal at day 40. Studies on the vaginal tissues of the adult animals that had been treated with steroids in the newborn period showed that there were permanent alterations of rates of DNA, protein, and RNA synthesis in those tissues, and that those changes apparently occurred with out modification of the fundamental characteristic of specific binding of estrogen by the vagina.3

Some Characteristics of Acid Injury and Recovery of Salmonella bareilly in a Model System

1981 ◽  
Vol 44 (1) ◽  
pp. 73-77 ◽  
Author(s):  
L. C. BLANKENSHIP
Keyword(s):  
Acetic Acid ◽  
Electron Transport ◽  
Enzyme Activities ◽  
Rna Synthesis ◽  
Saline Solution ◽  
Culture Media ◽  
Model System ◽  
Death Rates ◽  
Protein And Rna Synthesis ◽  
Casamino Acids

The injury and recovery characteristics of Salmonella bareilly after treatment with acetic acid in saline solution containing 0.5% sucrose were studied. Injury and death rates were dependent upon acid concentration and temperature. Several enzyme activities were substantially reduced in injured cells. Recovery rates were greater in peptones and casamino acids than in several commonly used culture media. The effects of a variety of inhibitors and antimetabolites on recovery of acid-injured cells indicated that protein and RNA synthesis, as well as electron transport, were necessary for recovery.

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

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).

Stimulation of protein and RNA synthesis by methylmercury chloride in the liver of intact and adrenalectomized rats

1981 ◽  
Vol 47 (2) ◽  
pp. 113-123 ◽  
Author(s):  
Saburo Omata ◽  
Hidemi Tsubaki ◽  
Kenji Sakimura ◽  
Mitsuru Sato ◽  
Ryuji Yoshimura ◽  
...  
Keyword(s):  
Rna Synthesis ◽  
Methylmercury Chloride ◽  
Protein And Rna Synthesis ◽  
Adrenalectomized Rats ◽  
Stimulation Of

Regulation of the Synthesis of Ribulose-l,5-bisphosphate Carboxylase and Its Subunits in the Flagellate Chlorogonium elongatum. II. Coordinated Synthesis of the Large and Small Subunits

1981 ◽  
Vol 36 (11-12) ◽  
pp. 942-950 ◽  
Author(s):  
Peter Westhoff ◽  
Kurt Zimmermann ◽  
Frank Boege ◽  
Klaus Zetsche
Keyword(s):  
Rna Synthesis ◽  
De Novo ◽  
Fold Increase ◽  
Growth Conditions ◽  
Autotrophic Growth ◽  
De Novo Synthesis ◽  
Bisphosphate Carboxylase ◽  
Unicellular Green Alga ◽  
Protein And Rna Synthesis ◽  
Ribulosebisphosphate Carboxylase

Abstract Transfer of heterotrophically grown cells of the unicellular green alga Chlorogonium elongatum to autotrophic growth conditions causes a 10 -15 fold increase in the amount of the chloroplastic enzyme ribulose-1,5-bisphosphate carboxylase. This increase was found to be due to de novo synthesis. The relative proportions of large and small subunits of the enzyme do not change. Their ratio is close to 3.4, the proportions in weight of the two subunits in the holoenzyme. Continous labelling with [35S]sulfate reveals that the ratios of incorporation into large and small subunits are essentially the same in autotrophic and heterotrophic cells. Pulse-chase experiments show that the subunits are degraded synchronously. The coordinated subunit synthesis cannot be uncoupled using inhibitors of protein and RNA synthesis or high temperature of cultivation of the alga. The results suggests a very tightly coordinated synthesis of the large and small subunits of ribulosebisphosphate carboxylase.

RNA AND PROTEIN METABOLISM IN THE OVIDUCT AND ENDOMETRIUM OF THE EWE AT PRO-OESTRUS: REGULATION BY OESTRADIOL AND PROGESTERONE

1976 ◽  
Vol 69 (1) ◽  
pp. 57-66 ◽  
Author(s):  
B. G. MILLER
Keyword(s):  
Protein Metabolism ◽  
Hormonal Regulation ◽  
Luteal Phase ◽  
Rna Synthesis ◽  
Model System ◽  
Oestrous Cycle ◽  
Cell Content ◽  
Hormone Effects ◽  
As Effects

SUMMARY The effects on RNA and protein metabolism in the oviduct and endometrium at pro-oestrus of oestradiol and progesterone secreted during the oestrous cycle were examined, using the ovariectomized, hormone-treated ewe as a model system. Thirty ewes received hormone injections during a period of 13 days, according to schedules designed to simulate endogenous ovarian secretion of oestradiol and progesterone during the oestrous cycle. Hormone effects on RNA:DNA ratios and on rates of synthesis of protein and methylated RNA in vitro, as well as effects on oviducal and uterine weight, were examined. The results obtained suggest that endogenous ovarian hormones have the following effects in the intact ewe. The secretion of oestradiol at pro-oestrus rapidly increases rates of synthesis of protein and methylated RNA, and mean cell content of RNA in both the endometrium and oviduct. Oestradiol secreted during the previous luteal phase of the oestrous cycle markedly increases mean cell content of RNA and amounts of protein and methylated RNA synthesis occurring in both tissues at pro-oestrus. In the endometrium, progesterone secreted during the luteal phase increases the RNA: DNA ratio, and probably also the amounts of protein and methylated RNA synthesized at pro-cestrus, but there are no significant interactions between the effects of oestradiol and progesterone. Progesterone had no effect on either the amounts or rates of synthesis of protein or methylated RNA in the oviduct. The results are discussed in relation to the hormonal regulation of physiological functions of the oviduct and endometrium during the first few days after the onset of oestrus.

Sign in / Sign up

Export Citation Format

Share Document