Somatostatin promotes accumulation of phospholipids in regenerating liver tissue of rats

1991 ◽  
Vol 11 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Cedomila Milin ◽  
Biserka Radosevic-Stasic ◽  
Madena Kirigin ◽  
Visnja Hinic ◽  
Daniel Rukavina ◽  
...  
Keyword(s):  
Growth Factors ◽  
Rapid Growth ◽  
Liver Tissue ◽  
Specific Effect ◽  
Protein Accumulation ◽  
Regenerating Liver ◽  
Total Lipids ◽  
Tissue Contents

Effects of somatostatin (SOM) on tissue contents of proteins, total lipids and phospholipids were investigated in regenerating and intact liver tissue of Y-59 rats. Whereas SOM inhibited protein accumulation in regenerating liver, the hormone evoked and increase in total lipids, and specially in phosphatidylcholine, phosphatidylethnolamine, phosphatidylserine (PS) and phosphatidylinositol (PI). Since the same effects were not seen when intact liver was analyzed, it is assumed that SOM acts primarily on tissue stimulated to rapid growth. The increase of PS+PI fractions indicates a specific effect of SOM on the metabolism of phosphatidylinositides. Such an effect might result from the interference of the hormone with the action of growth factors that accelerate phosphatidylinositol breakdown.

Influence of malnutrition on humoral growth factors in plasma and liver tissue during liver regeneration

1993 ◽  
Vol 12 ◽  
pp. 15-16
Author(s):  
S. Skullman ◽  
T.E. Adrian ◽  
J. Permert ◽  
M. Wirén ◽  
J. Larsson
Keyword(s):  
Growth Factors ◽  
Liver Regeneration ◽  
Liver Tissue

Evidence that interaction of hepatocytes with the collecting (hepatic) veins triggers position-specific transcription of the glutamine synthetase and ornithine aminotransferase genes in the mouse liver

1991 ◽  
Vol 11 (12) ◽  
pp. 6050-6058
Author(s):  
F C Kuo ◽  
J E Darnell
Keyword(s):  
Blood Flow ◽  
Carbon Tetrachloride ◽  
Glutamine Synthetase ◽  
Liver Tissue ◽  
Mouse Liver ◽  
Hepatic Veins ◽  
Surgical Removal ◽  
Ornithine Aminotransferase ◽  
Regenerating Liver ◽  
Portal Veins

We previously demonstrated that glutamine synthetase (GS) and ornithine aminotransferase (OAT) mRNAs are expressed in the mouse liver acinus preferentially in pericentral hepatocytes, that is, those immediately surrounding terminal central veins (A.L. Bennett, K.E. Paulson, R.E. Miller, and J.E. Darnell, Jr., J. Cell Biol. 105:1073-1085, 1987, and F.C. Kuo, W.L. Hwu, D. Valle, and J.E. Darnell, Jr., Proc. Natl. Acad. Sci. USA, in press). We now show that hepatocytes surrounding large collecting hepatic veins but not portal veins also express these two mRNAs. The pericentral hepatocytes are the most distal hepatocytes with respect to acinar blood flow, whereas this is not necessarily the case for hepatocytes next to the large collecting hepatic veins. This result implies that it is contact with some hepatic venous element which signals positional expression. In an effort to induce conditions that change relationships between hepatocytes and blood vessels, regenerating liver was studied. After surgical removal of two-thirds or more of the liver, there was no noticeable change in GS or OAT expression in the remaining liver tissue during regeneration. However, treatment with carbon tetrachloride (CCl4), which specifically kills pericentral hepatocytes, completely removed GS- and OAT-containing cells and promptly halted hepatic transcription of GS. Repair of CCl4 damage is associated with invasion of inflammatory and scavenging cells, which remove dead hepatocytes to allow regrowth. Only when hepatocytes resumed contact with pericentral veins were the pretreatment levels of OAT and GS mRNA and high levels of GS transcription restored.

scholarly journals Induction of orientation of bacterial cellulose microfibrils by a novel terpenoid from Acetobacter xylinum

1973 ◽  
Vol 135 (1) ◽  
pp. 145-149 ◽  
Author(s):  
W. Geoffrey Haigh ◽  
Hans J. Förster ◽  
Klaus Biemann ◽  
Neil H. Tattrie ◽  
J. Ross Colvin
Keyword(s):  
Higher Plants ◽  
Specific Effect ◽  
Ring System ◽  
Acetobacter Xylinum ◽  
Cellulose Microfibrils ◽  
Common Mechanism ◽  
Bacterial Cells ◽  
Total Lipids ◽  
Crude Lipid ◽  
Saponifiable Fraction

1. The bacterium Acetobacter xylinum produces extracellular cellulose microfibrils that form a pellicle in the medium enmeshing the bacterial cells. These microfibrils may show some localized alignment, which can be seen as birefringence when the culture is viewed between crossed Polaroid sheets. 2. An increase in birefringence can be induced by the addition of small amounts of certain classes of lipids, particularly sterols, to the cultures. 3. A crude lipid extract from Acetobacter cells induced greatly increased birefringence when added to fresh cultures of this organism. 4. When the bacterial lipids were fractionated, most of the activity was recovered in a complex, polar lipid. The lipid is secreted into the medium during growth and is unstable. The non-saponifiable portion of this lipid is shown to be a 1:1 mixture of a saturated and a monounsaturated C35 tetrahydroxy terpene with a hopane ring system in the accompanying paper by Förster et al. (1973). The saturated molecule is referred to as tetrahydroxybacteriohopane. 5. Tetrahydroxybacteriohopane is itself capable of inducing birefringence in cultures as is 22-hydroxyhopane, which was also isolated from the non-saponifiable fraction of the total lipids. 6. The mechanism of induction of birefringence (orientation of microfibrils) is not known. This is unlikely to be a specific effect, since all the above compounds are active (intact lipid, tetrahydroxybacteriohopane, 22-hydroxyhopane), as are other classes of lipid. It is suggested, however, that a common mechanism may be involved and that similar compounds may be concerned with control of microfibril alignment in the cells of higher plants.

Humoral growth factors in plasma and liver tissue during liver regeneration and malnutrition

1994 ◽  
Vol 6 (9) ◽  
pp. 797-802 ◽  
Author(s):  
Stefan Skullman ◽  
Thomas E. Adrian ◽  
Johan Permert ◽  
Jörgen Larsson
Keyword(s):  
Growth Factors ◽  
Liver Regeneration ◽  
Liver Tissue

486 Stellate-Like Mesenchymal Stem Cells Cultured from Omentum-Induced Regenerating Liver Tissue

2009 ◽  
Vol 136 (5) ◽  
pp. A-78
Author(s):  
Nishit Pancholi ◽  
Mark Kraus ◽  
Jilpa Patel ◽  
Krishnamurthy P. Gudehithlu ◽  
Perianna Sethupathi ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Liver Tissue ◽  
Regenerating Liver ◽  
Cells Cultured

scholarly journals Evidence that interaction of hepatocytes with the collecting (hepatic) veins triggers position-specific transcription of the glutamine synthetase and ornithine aminotransferase genes in the mouse liver.

1991 ◽  
Vol 11 (12) ◽  
pp. 6050-6058 ◽  
Author(s):  
F C Kuo ◽  
J E Darnell
Keyword(s):  
Blood Flow ◽  
Carbon Tetrachloride ◽  
Glutamine Synthetase ◽  
Liver Tissue ◽  
Mouse Liver ◽  
Hepatic Veins ◽  
Surgical Removal ◽  
Ornithine Aminotransferase ◽  
Regenerating Liver ◽  
Portal Veins

We previously demonstrated that glutamine synthetase (GS) and ornithine aminotransferase (OAT) mRNAs are expressed in the mouse liver acinus preferentially in pericentral hepatocytes, that is, those immediately surrounding terminal central veins (A.L. Bennett, K.E. Paulson, R.E. Miller, and J.E. Darnell, Jr., J. Cell Biol. 105:1073-1085, 1987, and F.C. Kuo, W.L. Hwu, D. Valle, and J.E. Darnell, Jr., Proc. Natl. Acad. Sci. USA, in press). We now show that hepatocytes surrounding large collecting hepatic veins but not portal veins also express these two mRNAs. The pericentral hepatocytes are the most distal hepatocytes with respect to acinar blood flow, whereas this is not necessarily the case for hepatocytes next to the large collecting hepatic veins. This result implies that it is contact with some hepatic venous element which signals positional expression. In an effort to induce conditions that change relationships between hepatocytes and blood vessels, regenerating liver was studied. After surgical removal of two-thirds or more of the liver, there was no noticeable change in GS or OAT expression in the remaining liver tissue during regeneration. However, treatment with carbon tetrachloride (CCl4), which specifically kills pericentral hepatocytes, completely removed GS- and OAT-containing cells and promptly halted hepatic transcription of GS. Repair of CCl4 damage is associated with invasion of inflammatory and scavenging cells, which remove dead hepatocytes to allow regrowth. Only when hepatocytes resumed contact with pericentral veins were the pretreatment levels of OAT and GS mRNA and high levels of GS transcription restored.

Insulin-like growth factor receptors in chicken liver membranes: binding properties, specificity, developmental pattern and evidence for a single receptor type

1990 ◽  
Vol 125 (2) ◽  
pp. 199-206 ◽  
Author(s):  
M. J. Duclos ◽  
C. Goddard
Keyword(s):  
Growth Factors ◽  
Rapid Growth ◽  
Chicken Liver ◽  
Affinity Constant ◽  
Type I ◽  
Liver Growth ◽  
Α Subunit ◽  
Single Receptor ◽  
Igf I ◽  
Insulin Like Growth Factors

ABSTRACT Two distinct receptors for the insulin-like growth factors (IGF-I and IGF-II) have been identified in mammalian tissues, but so far only a receptor structurally related to the type I receptor has been identified in chicken embryonic tissues. This study was designed to characterize binding sites for IGF peptides in chicken liver microsomal membranes prepared from hatch to 10 weeks of age which is the period of most rapid growth. Binding of both human (h) IGF-I and hIGF-II was displaceable by either peptide and exhibited similar pH, time and temperature dependency. Human IGF-II was more potent than hIGF-I in competing for the binding of the iodinated ligands with half-maximum effective concentrations of 3–5 μg/l and 7–13 μg/l respectively. Porcine insulin was also a potent competitor. Affinity cross-linking studies, followed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis under reducing conditions demonstrated that both IGF peptides were linked to a protein with a molecular weight of about 130 000 Da characteristic of the α-subunit of the type I receptor. There was no evidence for the presence of a type II receptor similar to that found in mammals. Specific binding of both peptides was low on the day of hatch, increased about threefold by day 3 of age and remained high for the first 3 weeks of life before returning to a lower steady state level up to 10 weeks of age. This was the result of variation in receptor number, with no change in the affinity of the binding site for either ligand. The affinity constant for IGF-II (4·5 ± 0·5 (s.e.m.) litres/nmol) was higher than for IGF-I (1·4 ± 0·3 litres/nmol). Insulin-like growth factors have previously been reported to stimulate the metabolism and growth of hepatocytes in vitro and are produced by these cells. The occurrence of a higher number of receptors at the period of most rapid growth of the liver suggests that they may have a role in regulating normal liver growth in an autocrine or paracrine manner. Furthermore, present evidence suggests that this is through a single receptor related to the type I receptor. Journal of Endocrinology (1990) 125, 199–206

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