The oestrogen-stimulated synthesis of heterogeneous nuclear ribonucleic acid in the uterus of immature rats.
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ABSTRACT:
SUBMITTER: Knowler JT
PROVIDER: S-EPMC1177528 | biostudies-other | 1973 Apr
REPOSITORIES: biostudies-other
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Project description:cDNA (complementary DNA) complementary to the abundant sequences of mRNA isolated from oestrogen-stimulated uterus was hybridized to polyadenylated and non-polyadenylated uterine hnRNA (heterogeneous nuclear RNA). High-molecular-weight polyadenylated hnRNA, isolated under denaturing conditions, was able to saturate the cDNA, but complementary sequences were low abundance when compared with homologous mRNA. The mRNA sequence content of the polyadenylated hnRNA increased considerably during oestrogen-induced growth of the uterus. Non-polyadenylated hnRNA also contained sequences complementary to the cDNA.
| S-EPMC1162519 | biostudies-other
Project description:Oestradiol-17beta and oestriol both sequentially stimulate the synthesis of heterogeneous nuclear RNA and rRNA in vivo. However, the stimulation by oestradiol-17beta, particularly of rRNA synthesis, is very much greater than that elicited by oestriol.
| S-EPMC1183877 | biostudies-other
Project description:The kinetics of the synthesis of the components of polyribosomes was investigated in the uterus of the immature rat responding to the administration of oestradiol-17 beta. The hormone brings about a rapid stimulation of the association of newly synthesized mRNA with uterine ribosomes, which is maximal 2-4 h after oestradiol administration and causes the aggregation of pre-existing ribosomes into polyribosomes. Despite the striking stimulation of rRNA synthesis 2-4 h after hormone treatment [Knowler & Smellie (1971) Biochem. J. 125, 605-614], the accumulation of new rRNA into ribosomes does not reach a peak until 12 h after administration. At this time, the incorporation of new ribosomal protein is also maximal. A second peak of incorporation of newly synthesized mRNA into polyribosomes follows the peak of ribosome synthesis and coincides with the oestrogen-activated synthesis of DNA.
| S-EPMC1161590 | biostudies-other
Project description:Stimulation of incorporation of labelled precursors into the RNA of immature rat uterus is an early result of oestradiol-17beta action. However, the extent of the increased incorporation varies with the mode of administration of the labelled precursors and with the weight of the rat. At the age and weight range normally used response is maximal at ten times control incorporation, 4h after the administration of 0.3mug or more of oestradiol-17beta. Under these conditions the stimulation of incorporation into the acid-soluble fraction is only 2-2.5-fold. When the purified RNA is separated on polyacrylamide gels the major increase in incorporation of radioactive precursor is found in rRNA and 4S RNA; the formation of the former has been followed from the 45S precursor. Preceding these events by at least 30min, however, is an increase in the incorporation of precursor into RNA species of very high molecular weight, which remained in the first few slices of the gel. The possible significance of these findings is discussed. The increased synthesis of rRNA in response to oestradiol-17beta is more strongly inhibited by actinomycin D than the synthesis of other RNA species. Cycloheximide, depending on time of administration and dosage, inhibits either RNA synthesis or the maturation of rRNA.
| S-EPMC1178098 | biostudies-other
Project description:Investigations were conducted to quantify activity of uteroglobin mRNA and secretion of uteroglobin in rabbit uterus after administration of progesterone and 5alpha-dihydrotestosterone, either alone or concomitantly with oestradiol-17beta and tamoxifen, a non-steroidal anti-oestrogen. Poly(A)-containing mRNA was isolated from the uterine tissue by extraction with phenol/chloroform, precipitation with ethanol and chromatography on oligo(dT)-cellulose. Cell-free translation in vitro of the poly(A)-containing mRNA was carried out in a wheat-germ lysate, and the product isolated by specific immuno-precipitation with anti-uteroglobin antiserum purified by affinity chromatography. Radioimmunoassay was utilized to determine uteroglobin content in the uterine flushings and tissue preparations. When given for 5 days, both progesterone (1mg/kg per day) and 5alpha-dihydrotestosterone (25mg/kg per day) elicited a marked induction of uteroglobin secretion, which was accompanied with accumulation of uteroglobin mRNA in the tissue. Concomitant administration of oestradiol-17beta (50mug/kg per day) or tamoxifen (12.5mg/kg per day) significantly decreased both progesterone- and 5alpha-dihydrotestosterone-induced uteroglobin secretion, with a parallel decrease in the uteroglobin-mRNA activity. The decline in the uteroglobin content of the uterine flushes brought about by oestradiol-17beta or tamoxifen administration was not due to inhibition of secretion of this protein by the endometrial cells, since a simultaneous decrease occurred in the tissue uteroglobin content. After a 5-day pretreatment with progesterone (1mg/kg per day), administration of oestradiol-17beta (50mug/kg per day) during the ensuing 4 days greatly accelerated the decay of the uteroglobin content in the uterine fluid.
| S-EPMC1161086 | biostudies-other
Project description:Measurements of the endogenous RNA polymerase activities of nuclei isolated from immature rabbit uteri have shown that prior treatment of the animals with oestradiol-17beta has a profound effect on the apparent activities of both RNA polymerases A and B. Within 1 h of hormone treatment, the activity of RNA polymerase A is increased and continues to rise until about 4h when it reaches a plateau and remains steady until at least 8h. The activity of RNA polymerase B increases sharply after oestradiol treatment reaching an early maximum at 30-45 min. Thereafter this activity declines until by 1-2h it approaches control values but a second increase in activity then occurs with a maximum at 3-4h. Treatment of the rabbits with alpha-amanitin before the administration of oestradiol inhibits the hormone-induced stimulation of RNA polymerase A activity in isolated nuclei but when the administration of alpha-amanitin is delayed until after the early rise of RNA polymerase B activity, the oestradiol-induced stimulation of RNA polymerase A is retained. Similar results have been obtained in experiments with cycloheximide suggesting that the stimulation of RNA polymerase A activity by oestradiol is dependent on the hormone-induced stimulation of RNA polymerase B and the subsequent synthesis of protein using the RNA product of the early increase in RNA polymerase B activity. Measurement of the activities of RNA polymerases A and B after isolation of the enzymes from immature rabbit uterine nuclei before and after oestradiol treatment failed to show any differences. Therefore it would appear that the changes in the observed activities of RNA polymerases A and B in isolated nuclei are consequences of changes in the structure and function of chromatin rather than the results of modifications in the RNA polymerases themselves.
| S-EPMC1165378 | biostudies-other
Project description:1. After treatment of immature rats with diethylstilboestrol, the wet weight and RNA content of uterine tissue increased rapidly, reaching a peak at 40hr. After an initial lag of a few hours, the acid-soluble ribose and protein contents also rose to maxima at 40hr. No increase in DNA content occurred until at least 24hr. after treatment. 2. The RNA from immature rat uterus isolated at various times up to 6hr. after administration of oestradiol-17beta was labelled by injecting [(3)H]uridine and [(3)H]guanosine intraperitoneally 30min. before the animals were killed. It was fractionated on columns of kieselguhr coated with methylated serum albumin and the radioactivity in fractions corresponding to transfer RNA, 7s RNA, ribosomal RNA, Q(1)-RNA, Q(2)-RNA and DNA-like RNA was determined. 3. The radioactivity of the whole RNA increased steadily for 6hr. after hormone treatment. The earliest changes occurred in the Q(1)-RNA (ribosomal RNA precursor), whereas at longer time-intervals the radioactivity of the ribosomal RNA, 7s RNA and transfer RNA increased by four- to five-fold. The radioactivity of the DNA-like RNA increased by about 50%, but only at the longer time-intervals. 4. It is concluded that one of the earliest changes in response to oestradiol treatment is a major increase in synthesis of ribosomal RNA followed later by a similar increase in synthesis of transfer RNA and by a much smaller increase in synthesis of DNA-like RNA. The change in synthesis of ribosomal RNA in immature rat uterus may represent one of the most important responses to oestradiol treatment.
| S-EPMC1187757 | biostudies-other
Project description:Changes in RNA synthesis in liver nuclei were observed at different ages and after hypophysectomy and hormone replacement in female Sprague-Dawley rats. As determined by the incorporation of [3H]UMP into an acid-insoluble product, RNA synthesis decreased by about 75% in intact rats from 6 months to 24 months of age. This decline with age was not observed in liver nuclei from 24-month-old rats that had been hypophysectomized at 12 months and maintained on a minimal hormone-replacement therapy. Thyroid hormones and somatotropin (growth hormone) had an additive effect on RNA synthesis in liver nuclei from these hypophysectomized rats. The same hormones had no significant effect on intact, age-matched rats. With advancing age, nuclei of intact rats had an increase in the pool of free RNA polymerase and an apparent decrease in the enzyme activity bound to nuclear chromatin. There was no change in total enzyme with age. In hypophysectomized, hormone-treated rats, free RNA polymerase activity decreased and chromatin-bound activity increased. There was no difference in total nuclear RNA polymerase activity between operated or intact rats. However, the ratio of the bound to the free activity was different. These results suggest that the ability of RNA polymerase to bind to chromatin may be involved in the age-related decrease in liver nuclear RNA synthesis of intact rats.
| S-EPMC1161852 | biostudies-other
Project description:1. The nuclear-myofibrilar (800g pellet) fraction of the uterus from immature (22-23 days old) rats not exposed to oestrogen exhibits saturable binding of oestradiol. The nuclear binding capacity represents approximately 10% of that of the cytosol fraction (approx. 3.5 fmol/mug of DNA). The predominant part (0.3.5 fmol/mug of DNA) of the nuclear binind sites are present in the residual pellet after extraction with 0.5 M-KC1. 2. By using an exchange technique in vitro, determinations of the nuclear binding sites have been carried out after administration of 1 mug of oestradiol in vivo. Within 0.5h after the hormone injection, the concentration of nuclear bindng sites increased to approx. 0.4 fmol/mug of DNA in the 0.5 M-KC1-extractable fraction, and to approx. 1.2 fmol/mug of DNA in the residual fraction. Meanwhile the cytosol oestrogen-receptor concentration decreased to approx. 10% of its initial value. In the following period from 0.5 h after the oestradiol injection onwards, the concentration of nuclear oestrogen receptors decreased with halflife values of approx. 140 and 200 min for the KC1(0.5 M)-extractable and residual form respectively. At the same time, the cytosol receptor concentration increased to reach approx. 50% of the initial value by the 6h. This increase could not be blocked by cycloheximide. The initial concentration of cytosol receptor was restored approx. 11h after the injection and the increase during the 6-11h period was sensitive to cycloheximide inhibition, suggesting protein-synthesis-dependence of the process. 3. With the (more) physiological dose of oestradiol (0.1 mug), the decrease the cytosol receptor was only 50% by 4h and this was followed by a period (up to 12h after injection) during which the initial concentration was restored. During this period the increase of the receptor can be blocked by cycloheximide.
| S-EPMC1165351 | biostudies-other
Project description:An early response to the administration of oestradiol-17 beta to immature rats is a dramatic stimulation in the synthesis of uterine hnRNA (heterogenous nuclear RNA). High-molecular-weight fractions of the hnRNA were purified and subfractionated on poly(U)-Sepharose into fractions that differed in their poly(A) content and their size profile on polyacrylamide gels. Oestrogen treatment of the rats stimulated the synthesis of all three fractions of high-molecular-weight hnRNA, but the kinetics of synthesis, degree of stimulation and size distribution of the newly synthesize RNA differed in each fraction.
| S-EPMC1185734 | biostudies-other