Effect of hypophysectomy on liver nuclear ribonucleic acid synthesis in aging rats

Bolla, R. I.; Denckla, W D

doi:10.1042/bj1840669

Cited by 39 publications

(16 citation statements)

References 29 publications

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“…No changes in the level of RNase activity were observed between the adult and senes cent Wistar rat liver nuclei as also reported with nuclei isolated from other strains of rats [7,13] and from mice [9], However, the present results suggest that the RNA (or some fraction of it) synthesized by senescent nuclei may be somewhat more susceptible to RNase than is the RNA synthesized by adult nuclei. This intriguing possibility deserves further study.…”

Section: Discussioncontrasting

confidence: 51%

“…Several studies [7,9,13,16,28] have shown that RNA synthesis by liver nuclei isolated from various strains of senescent rats (24-30 months) or mice (25-30 months) is decreased compared, respec tively, to nuclei isolated from adult rats (12 months) or mice (8-10 months). The present results show that both the rate and the max imal level of RNA synthesis by liver nuclei isolated from senescent (22-26 months) fe male Wistar rats also are decreased com pared to adult (12 months) animals.…”

Section: Discussionmentioning

confidence: 99%

“…The procedure of Bolla and Denckla [7] was mod ified: 5 X 106 nuclei were incubated at 37 °C for 15 min in 0.2 ml of medium II containing 0.6 pCi [3H]-UTP (specific activity, 37 Ci/mmol). Assays for chromatin-free RNA polymerase activity, i.e., activity not bound to the endogenous DNA template, additionally contained 40 pg/ml poly d[A-T] as template plus 20 gg/ml actinomycin D. Assays for chromatin-bound activity contained neither actinomycin DNA nor poly d[A-T].…”

Section: Chromatin-bound and Chromatin-free Rna Polymerase Activitiesmentioning

confidence: 99%

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RNA Synthesis by Nuclei and Chromatin Isolated from Adult and Senescent Wistar Rat Liver

Park¹,

Buetow²

1990

Gerontology

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Nuclei isolated from senescent (22–26 months) female Wistar rat liver show a decreased RNA synthesis compared to nuclei from adult (12 months) liver. Kinetic analyses demonstrate a decreased rate (25–42%) and maximal incorporation (41–54%) of labeled uridine triphosphate into both rRNA and mRNA in senescent nuclei. Chromatin-bound RNA polymerase activity is decreased by 36%, whereas free RNA polymerase activity, i.e., not bound to chromatin, is increased by 41 % in senescent nuclei, but the total bound plus free activity is the same in senescent and adult nuclei. Isolated senescent chromatin shows reduced transcriptional capacity and requires a higher temperature to initiate melting. A decreased ability of chromatin to bind RNA polymerases appears to underlie the observed decreased RNA synthesis in senescent liver nuclei.

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Section: Discussioncontrasting

confidence: 51%

Section: Discussionmentioning

confidence: 99%

Section: Chromatin-bound and Chromatin-free Rna Polymerase Activitiesmentioning

confidence: 99%

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RNA Synthesis by Nuclei and Chromatin Isolated from Adult and Senescent Wistar Rat Liver

Park¹,

Buetow²

1990

Gerontology

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“…However, there are no alterations in RNA polymerase activity along the lifespan (33), which indicates that low RNA synthesis in old animals would be a consequence of increased chromatin packing states, and not of reduced polymerase activity (31). Many studies involving chromatin resistance to digestion by restriction enzymes and nucleases showed a compactness increase in chromatin packing with aging (34)(35)(36).…”

mentioning

confidence: 99%

Chromatin supraorganization and extensibility in mouse hepatocytes with development and aging

2007

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In May 2000, the Board of Directors of the American Society for Information Science (ASIS) changed the name of the association by adding the words, “and Technology” (&T). Today this change may be considered minor, but for many involved at the time—it was a change that had purpose and meaning. A study was initiated to trace the society's transition toward a professional association more inclusive of practitioners and applied research. The study was conducted in two stages, using quantitative and qualitative methods. Stage 1 compared the research published in the conference proceedings both prior to and following the society's name change. Stage 2 built upon the assumption that a professional association is a reflection of its membership. The Stage 1 results offer both an aggregate and a comparative view of the papers accepted for and presented at the annual conference. The results suggest that as an association of researchers, the society may be moving toward a renewed focus on practical and applied information. The Stage 2 results suggest that some ASIS&T members welcome the increased focus on technology, applied research, and the topics of interest to practitioners. Others view the changes as negative, perhaps even undermining the value of ASIS. The practical implications suggest that an annual conference can be an association's most important branding opportunity. It should reflect the interests of its membership as well as attract new members. A clear vision, supported by the membership, will guide the activities of the society and, in turn, will effectively serve its members professional needs.

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“…Thus, RNA polymerase I activity in isolated liver nuclei was reported to be stimulated after the administration of hormones such as glucocorticoids (Jacob et al, 1969 ;Yu and Feigelson, 1971;Sekeris and Schmidt, 1973;Todhunter et al, 1978;Grote et al, 1983;Matsui et al, 1986), thyroid hormones Zoncheddu et al, 1977;Igarashi et al, 1980), androgen and somatotropin Salaman et al, 1972;Bolla and Denckla, 1979). The underlying molecular mechanisms involved in the regulation, however, remain unclear.…”

mentioning

confidence: 99%

In Vivo Effects of Thyroid Hormone, Glucocorticoid, Androgen, and Somatotropin on RNA Polymerase I Activities in Isolated Liver Nuclei.

1988

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In the `template-engaged' form activity of RNA polymerase I in nuclei of normal rat livers, about 40% of the activity was found to be influenced by thyroid hormones and glucocorticoids and can be eliminated by 1h treatment with cycloheximide. On the other hand, the `free' form activity of the enzyme in rat liver nuclei and the total amount of the enzyme in nucleoli were scarcely affected by these hormones. These results suggest that a considerable portion of rRNA synthesis in rat liver nucleoli is regulated by the initiation of rDNA transcription, probably with the participation of glucocorticoid-and thyroid hormone-dependent short-lived protein(s). When somatotropin, in addition to glucocorticoids and thyroid hormones, was depleted by hypophysectomy, the `template-engaged' form activity of RNA polymerase I was reduced to 3'0% of the normal level. The activity was restored completely by a single injection of triiodothyronine plus somatotropin, but not by injections of the individual hormones. From these results, it is likely that the stimulating effects of glucocorticoids and thyroid hormones on rRNA synthesis are maintained by the action of somatotropin which seems to occur in a different mechanism from those of the former two hormones.In contrast to these hormones, androgen showed no acute effect on `template-engaged' form activity of RNA polymerase I in liver nuclei.

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Effect of hypophysectomy on liver nuclear ribonucleic acid synthesis in aging rats

Cited by 39 publications

References 29 publications

RNA Synthesis by Nuclei and Chromatin Isolated from Adult and Senescent Wistar Rat Liver

RNA Synthesis by Nuclei and Chromatin Isolated from Adult and Senescent Wistar Rat Liver

Chromatin supraorganization and extensibility in mouse hepatocytes with development and aging

In Vivo Effects of Thyroid Hormone, Glucocorticoid, Androgen, and Somatotropin on RNA Polymerase I Activities in Isolated Liver Nuclei.

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