scholarly journals Hydrocortisone stimulation of RNA synthesis in induction of hepatic enzymes

1965 ◽  
Vol 66 (S1) ◽  
pp. 125-136 ◽  
Author(s):  
Francis T. Kenney ◽  
Wesley D. Wicks ◽  
David L. Greenman
Keyword(s):  
Rna Synthesis ◽  
Hepatic Enzymes ◽  
Stimulation Of

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.

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

EFFECT OF 3′:5′-CYCLIC AMP ON NUCLEAR AND MITOCHONDRIAL RNA SYNTHESIS OF RAT ADRENOCORTICAL CELLS

1972 ◽  
Vol 70 (1) ◽  
pp. 81-88 ◽  
Author(s):  
G. G. Nussdorfer ◽  
G. Mazzocchi
Keyword(s):  
Cyclic Amp ◽  
Rna Synthesis ◽  
Mitochondrial Rna ◽  
Adrenocortical Cells ◽  
Hypophysectomized Rats ◽  
High Resolution Autoradiography ◽  
Intracellular Mediators ◽  
Stimulation Of ◽  
Trophic Action

ABSTRACT The effect of 3′:5′-cyclic AMP (cAMP) on the incorporation of 3H-uridine into adrenocortical cells of hypophysectomized rats was investigated by high resolution autoradiography. The quantitative analysis of autoradiographs shows that cAMP, like ACTH, enhances the tracer incorporation into both nuclei and mitochondria. These findings are discussed in relation to the results of various investigations, indicating that cAMP functions as an intracellular mediator of the long-term trophic action of ACTH on the adrenal cortex. It is suggested that the mechanism of this action of cAMP consists in the stimulation of both nuclear and mitochondrial RNA synthesis. Furthermore, the possibility that the trophic action of ACTH on the adrenal gland involves other intracellular mediators, as well as cAMP, is suggested.

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.

THE EFFECT OF PARATHYROID EXTRACT ON CELLULAR ACTIVITY AND PLASMA CALCIUM LEVELS IN VIVO

1969 ◽  
Vol 45 (3) ◽  
pp. 387-400 ◽  
Author(s):  
PATRICIA J. BINGHAM ◽  
IRIS A. BRAZELL ◽  
MAUREEN OWEN
Keyword(s):  
Rna Synthesis ◽  
Time Lag ◽  
Plasma Calcium ◽  
Cellular Activity ◽  
Maximum Increase ◽  
Cytoplasmic Rna ◽  
Significant Stimulation ◽  
Parathyroid Extract ◽  
Stimulation Of

SUMMARY Parathyroid hormone has a direct effect on the osteoclast population present at the time of administration of the hormone. There was a significant stimulation of nuclear RNA synthesis at the earliest time (1½ hr.) at which the measurement could be made. This is followed by increased production of cytoplasmic RNA which reaches its maximum after a considerable time-lag (7 to 12 hr. after parathyroid extract (PTE)). The increase in cytoplasmic RNA is accompanied by a corresponding stimulation of protein and mucoprotein synthesis in the osteoclasts and the effect persists at least until 24 hr. This time-lag and the relatively long duration of the effect on protein synthesis can be correlated approximately with the effect on the plasma calcium level. It is suggested therefore that the rise in plasma calcium is mainly due to the increased cellular activity of the osteoclasts and the resulting increased bone resorption. The opposite effect on the osteoblast system has about the same time-sequence and would complement the effect on the osteoclast system. At about the same time as the maximum increase in cellular activity in the osteoclasts is observed, a significant effect on RNA synthesis in the endosteal mesenchymal cells, the precursors of the osteoclasts, becomes apparent. This is closely followed by a rise in the number of osteoclasts which is first apparent at 17 hr. after PTE and is maximal by 24 hr. Consequently, the rise in the number of osteoclasts is a secondary effect and is not responsible for the initial rise in plasma calcium which occurred much earlier. It is suggested that the increase in osteoclast numbers follows as a result of the increased metabolic activity of the osteoclast population present when the hormone was injected. There is a depression of RNA synthesis in both the osteoblasts and their precursors, the preosteoblasts. This means that the hormone has opposite effects, not only on the osteoblasts and osteoclasts, but also on their respective precursors, indicating that osteoprogenitor cells contain a mixture of cells with two main lines, those differentiating in an osteoblastic or osteoclastic direction, respectively.

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