RNA SYNTHESIS IN THE RAT ANTERIOR HYPOTHALAMUS AND PITUITARY: RELATION TO NEONATAL ANDROGEN AND THE OESTROUS CYCLE

1970 ◽  
Vol 48 (1) ◽  
pp. 125-137 ◽  
Author(s):  
D. F. SALAMAN
Keyword(s):  
Ribosomal Rna ◽  
Anterior Pituitary ◽  
Rna Synthesis ◽  
Specific Activity ◽  
Gradient Centrifugation ◽  
Anterior Hypothalamus ◽  
Oestrous Cycle ◽  
Uridine Incorporation ◽  
Cyclic Changes

SUMMARY RNA from the anterior hypothalamus and anterior pituitary of rats has been labelled by incubation in vitro with [3H]uridine and characterized by density gradient centrifugation. A study of normal females during the oestrous cycle showed cyclic changes in [3H]uridine incorporation into rapidly labelled RNA (rl-RNA) both in the anterior pituitary and hypothalamus. In both tissues the specific activity of RNA was low at dioestrus and high at oestrus and metoestrus. In androgenized females, incorporation into hypothalamic rl-RNA was less than the oestrus—metoestrus level and similar to that at dioestrus, while incorporation into anterior pituitary rl-RNA was similar to the oestrus—metoestrus level and greater than at dioestrus. [3H]Uridine incorporation into ribosomal RNA (r-RNA) of anterior hypothalamus and pituitary was also demonstrated by incubation for 4 h. Under these conditions there was no effect of androgenization on hypothalamic r-RNA, but the specific activity of pituitary r-RNA was greater than normal.

IN VITRO UPTAKE OF TRITIATED OESTRADIOL BY THE RAT ANTERIOR HYPOTHALAMUS DURING THE OESTROUS CYCLE

1970 ◽  
Vol 63 (4) ◽  
pp. 577-584 ◽  
Author(s):  
Junzo Kato
Keyword(s):  
Posterior Hypothalamus ◽  
Anterior Hypothalamus ◽  
Oestrous Cycle ◽  
Physiological Regulation ◽  
Cortex Cerebri ◽  
Anterior Hypophysis ◽  
Cyclic Changes ◽  
In Vitro Uptake

ABSTRACT The anterior, middle and posterior hypothalamus, the cortex cerebri, the anterior hypophysis, and the diaphragm of postpubertal rats at different phases of the oestrous cycle were incubated in vitro with tritiated 17β-oestradiol. Uptake of radioactivity by the anterior hypothalamus at prooestrus and oestrus was lower than that at dioestrus. In contrast no fluctuation in the concentration of the radioactivity in the other parts of brain, the hypophysis and muscle was observed during the oestrous cycle. These in vitro findings are consistent with the in vivo observations of cyclic changes in phase with the oestrous cycle of the amount of radioactive oestradiol taken up by the anterior hypothalamus following the injection of tritiated oestradiol (Kato et al. 1969b). Thus it is further suggested that the oestradiol receptor in the anterior hypothalamus of the rat is involved in the physiological regulation and maintenance of cyclic changes in the hypothalamo-pituitary system through the mechanism of action of feedback of oestrogen.

scholarly journals DIFFERENTIATION OF DROSOPHILA CELLS LACKING RIBOSOMAL DNA, IN VITRO

Genetics ◽  
1973 ◽  
Vol 73 (3) ◽  
pp. 429-434
Author(s):  
J James Donady ◽  
R L Seecof ◽  
M A Fox
Keyword(s):  
Drosophila Melanogaster ◽  
Ribosomal Rna ◽  
Ribosomal Dna ◽  
Rna Synthesis ◽  
Wild Type ◽  
Drosophila Cells

ABSTRACT Drosophila melanogaster embryos that lacked ribosomal DNA were obtained from appropriate crosses. Cells were taken from such embryos before overt differentiation took place and were cultured in vitro. These cells differentiated into neurons and myocytes with the same success as did wild-type controls. Therefore, ribosomal RNA synthesis is not necessary for the differentiation of neurons and myocytes in vitro.

scholarly journals Biosynthesis of growth hormone in the rat anterior pituitary gland. Stimulation of biosynthesis in vitro by insulin

1973 ◽  
Vol 134 (4) ◽  
pp. 1103-1113 ◽  
Author(s):  
A. Betteridge ◽  
M. Wallis
Keyword(s):  
Growth Hormone ◽  
Anterior Pituitary ◽  
Rna Synthesis ◽  
Glucose Utilization ◽  
Actinomycin D ◽  
Hormone Synthesis ◽  
Pituitary Glands ◽  
Hormone Biosynthesis ◽  
Stimulation Of

The effect of insulin on the incorporation of radioactive leucine into growth hormone was investigated by using rat anterior pituitary glands incubated in vitro. A 50% stimulation over control values was observed at insulin concentrations above 2μm (280munits/ml). The effect was specific for growth hormone biosynthesis, over the range 1–5μm-insulin (140–700munits/ml). Lower more physiological concentrations had no significant effect in this system. Above 10μm (1.4 units/ml) total protein synthesis was also increased. The stimulation of growth hormone synthesis could be partially blocked by the addition of actinomycin D, suggesting that RNA synthesis was involved. Insulin was found to stimulate the rate of glucose utilization in a similar way to growth hormone synthesis. 2-Deoxyglucose and phloridzin, which both prevented insulin from stimulating glucose utilization, also prevented the effect of insulin on growth hormone synthesis. If glucose was replaced by fructose in the medium, the effect of insulin on growth hormone synthesis was decreased. We conclude that the rate of utilization of glucose may be an important step in mediating the effect of insulin on growth hormone synthesis.

Synthesis of RNA in oocytes of Xenopus laevis during culture in vitro

Development ◽  
1974 ◽  
Vol 32 (2) ◽  
pp. 515-532
Author(s):  
A. Colman
Keyword(s):  
Xenopus Laevis ◽  
In Vitro Culture ◽  
Ribosomal Rna ◽  
Rna Synthesis ◽  
Culture Medium ◽  
Salt Medium ◽  
Complex Media ◽  
18S Ribosomal Rna ◽  
Rna Precursor

RNA synthesis can be maintained in large oocytes of Xenopus laevis during periods of in vitro culture of at least 10 days. A simple salt medium, modified Barth's solution, is found to be as effective a culture medium for these oocytes as several other complex media. The newly synthesized RNA is characterized electrophoretically and shown to consist predominantly of ribosomal RNA precursor, 28S and 18S ribosomal RNA, and 4S RNA. The distribution of this RNA within the oocyte is detected autoradiographically, where it is found to be greatly concentrated over the nucleoli. No qualitative alterations in either of these parameters are found during culture, within the limits of sensitivity of the assay procedures.

The appearance and quantitation of cytoplasmic ribonucleic acid in the early chick embryo

Development ◽  
1972 ◽  
Vol 28 (2) ◽  
pp. 367-384
Author(s):  
C. C. Wylie
Keyword(s):  
Chick Embryo ◽  
Ribosomal Rna ◽  
Rna Synthesis ◽  
Specific Activity ◽  
Cell Number ◽  
Present Knowledge ◽  
Precursor Pool ◽  
Cytoplasmic Rna ◽  
Labelling Experiment ◽  
Neurula Stage

This paper seeks to extend our knowledge about RNA synthesis in early embryogenesis to the domestic fowl, Gallus domesticus. Using this species for research, apart from increasing our knowledge of higher vertebrate embryology, has certain advantages such as rapid uptake of isotopic precursors and ease of microdissection in culture. The following results are presented: (1) The cell number in the whole chick embryos is shown to be increasing logarithmically between the time of laying and the early neurula stage; with a doubling time of 7·4 h. (2) The onset of ribosomal RNA synthesis has been shown to be during mid-cleavage of the chick embryo, while development is taking place in the oviduct and uterus of the mother. (3) In a cumulative labelling experiment, embryos were labelled at the unincubated-egg stage, allowed to develop to various morphological stages up to neurulation, and their cytoplasmic RNA prepared and analysed by gel electrophoresis. (4) The specific activity of the precursor pool for RNA synthesis was measured at several stages, using the same labelling conditions, and the results were used to quantitate the RNA synthesis from the incorporated radioactivity. (5) Using these techniques, it was found that newly synthesized cytoplasmic RNA accumulates steadily in the whole chick embryo, reaching a level of 104 μg by the early neurula stage. On a per cell basis, however, the amount of newly synthesized cytoplasmic RNA seems to decrease slightly. These findings are discussed in the light of present knowledge about embryos of other vertebrates and certain invertebrates.

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.

Cellular heterogeneity of uridine incorporation in collecting tubules: effect of DOCA

1985 ◽  
Vol 248 (4) ◽  
pp. F552-F564
Author(s):  
A. Vandewalle ◽  
F. Cluzeaud ◽  
M. Chavance ◽  
J. P. Bonvalet
Keyword(s):  
Rna Synthesis ◽  
Cellular Heterogeneity ◽  
Nuclear Surface ◽  
Intercalated Cells ◽  
Uridine Incorporation ◽  
Collecting Tubules ◽  
Silver Grains ◽  
Stimulation Of

In previous studies we showed that in vitro uridine incorporation along the renal tubule is heterogeneous and that DOCA induces a stimulation of RNA synthesis in distal cortical and medullary structures. The present work examines by autoradiography of isolated tubules and renal tissue sections the cellular heterogeneity of the connecting (CNT) and cortical collecting (CCT) tubules after in vivo injection of [3H]uridine in normal and DOCA-treated rabbits. Data confirmed the profile of uridine incorporation along the tubule, which was found in in vitro experiments, and the DOCA-induced stimulation of RNA synthesis. In microdissected CNT and CCT of control kidneys, statistical analysis of the distribution of labeling revealed the presence of two distinct cell populations: one with low labeling (2-3 silver grains per nucleus) and one with high labeling (10-13), which represent 64 and 36%, respectively (CNT), and 74 and 26%, respectively (CCT), of the whole population. Histological data showed that the respective proportions of intercalated cells (29% in CNT; 21% in CCT) and connecting tubule cells (65%) or principal cells (79%) are close to those of the populations with high or low labeling. In addition, autoradiographs on renal sections directly demonstrated that the labeling of intercalated cells (19.3 silver grains/100 micron2 nuclear surface in CNT; 14.7 in CCT) was three times higher than that of connecting (6.6) or principal (5.8) cells. In isolated CNT and CCT, DOCA induced similar absolute increases in the labeling of the two populations. However, the relative increase was more than two times higher in the population with low labeling (+131% in CNT, +210% in CCT) than in the one with high labeling (+71% and +98%). We conclude that cell population of the collecting cortical tubule (CNT and CCT) is heterogeneous with regard to uridine incorporation, reflecting RNA synthesis.

Ribonucleic acid synthesis inPlasmodium knowlesimaintained bothin vivoandin vitro

Parasitology ◽  
1975 ◽  
Vol 71 (2) ◽  
pp. 199-209 ◽  
Author(s):  
P. I. Trigg ◽  
P. G. Shakespeare ◽  
Susan J. Burt ◽  
Sally I. Kyd
Keyword(s):  
Ribosomal Rna ◽  
Rna Synthesis ◽  
Nuclear Division ◽  
Plasmodium Knowlesi ◽  
Acid Synthesis ◽  
Agarose Gel Electrophoresis ◽  
Trophozoite Stage ◽  
Late Trophozoite

RNA extracted from purified parasites ofPlasmodium knowlesiwas fractionated using agarose gel electrophoresis. Preparations from parasites grown bothin vivoandin vitrocontained species of RNA with sedimentation coefficients of 4·0S, 5·0S, 16·6S, 24·2S, 31·4S, 38·0S and 48·3S. There was less RNA present in parasites grownin vitrothan the equivalent stage parasites grownin vivobut the proportional amounts of the various species of RNA was similar in both cases. It is suggested that the 24·2S and 16·6S species of RNA are ribosomal and that the high molecular weight 31·4S, 38·0S and 48·0S species are ribosomal precursors. Ribosomal RNA synthesis occurs throughout the cell cycle during growth from the ring to the schizont stage; maximum incorporation of [H3]-adenosine occurs at the late trophozoite stage before nuclear division.

scholarly journals Effect of H1 protein on in vitro ribosomal RNA synthesis

FEBS Letters ◽  
1974 ◽  
Vol 43 (1) ◽  
pp. 86-88 ◽  
Author(s):  
Andrew Travers ◽  
Regine Cukier-Kahn
Keyword(s):  
Ribosomal Rna ◽  
Rna Synthesis

In vitro protein synthesis, ribosomal RNA synthesis, and polyribosomes in senescing leaves of Perilla

1972 ◽  
Vol 1 (2) ◽  
pp. 79-90 ◽  
Author(s):  
James A. Callow ◽  
Maureen E. Callow ◽  
H.W. Woolhouse
Keyword(s):  
Protein Synthesis ◽  
Ribosomal Rna ◽  
Rna Synthesis ◽  
In Vitro Protein Synthesis ◽  
Vitro Protein
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