ABSTRACT
The magnetic field, the electron density, and the ion velocities in a multispecies plasma conducting a high fast-rising current are determined using simultaneous spectroscopic measurements. It is found that ion separation occurs in which a light-ion plasma is pushed ahead while a heavy-ion plasma lags behind the magnetic piston. We show that most of the momentum imparted by the magnetic field pressure is taken by the reflected light ions, and most of the dissipated magnetic field energy is converted into kinetic energy of these ions, even though their mass is only a small part of the total plasma mass. Such species separation with implications to the momenta and energy partitioning is shown to be of a general nature.
ABSTRACT
Nonmetabolizable fatty acids are shown here to induce adipose conversion of 3T3-L1 preadipocytes as well as to activate transcription of a reporter plasmid promoted by a peroxisome proliferators response element. This dual activity was also observed using the peroxisome proliferator bezafibrate or the differentiation inducer isobutyl methylxanthine. The data suggest a role for a peroxisome proliferators activated receptor (PPAR) in adipose conversion induced by fatty acids, isobutyl methylxanthine, or xenobiotic amphipathic carboxylates.
Subject(s)
Adipose Tissue/drug effects , Hypolipidemic Agents/pharmacology , Microbodies/drug effects , Receptors, Cytoplasmic and Nuclear/drug effects , Transcription Factors/drug effects , 1-Methyl-3-isobutylxanthine/pharmacology , 3T3 Cells , Animals , Bezafibrate/pharmacology , Cell Differentiation/drug effects , Chloramphenicol O-Acetyltransferase/analysis , Chloramphenicol O-Acetyltransferase/genetics , Hypoglycemic Agents/pharmacology , Mice , Palmitates/pharmacology , Palmitic Acids/pharmacology , Plasmids , Receptors, Cytoplasmic and Nuclear/genetics , Transcription Factors/genetics , Transcription, Genetic/drug effects , TransfectionABSTRACT
Induction of adipose conversion in 3T3-L1 by bezafibrate has been previously shown to be enhanced by dibutyryl cAMP and to be associated with an early phosphorylation of a 60 kDa acidic protein [Biochim. Biophys. Acta 1054 (1990) 219-224; FEBS Lett. 285 (1991) 63-65]. We describe here the isolation and sequencing of two peptides of the protein concerned. Both appear to be homologous with two respective amino acid sequences of the mouse intermediate filament protein vimentin.
Subject(s)
Adipocytes/metabolism , Vimentin/metabolism , 1-Methyl-3-isobutylxanthine/pharmacology , 3T3 Cells , Amino Acid Sequence , Animals , Bezafibrate/pharmacology , Bucladesine/pharmacology , Cell Differentiation/physiology , Electrophoresis, Gel, Two-Dimensional , Immunoblotting , Mice , Molecular Sequence Data , Molecular Weight , Peptide Fragments/chemistry , Phosphorylation , Sequence Homology, Amino Acid , Vimentin/chemistryABSTRACT
The induction of adipose conversion in 3T3-L1 cells by bezafibrate has been shown to be enhanced by dibutyryl-cAMP. We here report that the induction of adipose conversion in 3T3-L1 cells, by either bezafibrate and dibutyryl cAMP, or isobutylmethyxanthine alone, is associated with a very early phosphorylation of a 60-kDa acidic protein found in the nuclear fraction.
Subject(s)
Adipose Tissue/cytology , Bucladesine/pharmacology , Nuclear Proteins/metabolism , 1-Methyl-3-isobutylxanthine/pharmacology , Adipose Tissue/metabolism , Animals , Bezafibrate/pharmacology , Cell Differentiation/drug effects , Cell Line , Drug Synergism , Electrophoresis, Gel, Two-Dimensional , Fibroblasts , Mice , PhosphorylationABSTRACT
The induction of adipose conversion in 3T3-L1 cells by bezafibrate (Brandes, R., Hertz, R. Arad R., Naishtat S., Weil, S. and Bar-Tana, J. (1987) Life Sci., 40, 935-941) was enhanced by dibutyryl-cAMP as well as forskolin, theophylline or isobutylmethylxanthine added to the incubation medium together with the bezafibrate inducer. The synergistic effect of bezafibrate and dibutyryl-cAMP resulted in enhancing the expression of late markers of adipose conversion, e.g., lipid accumulation or glycerol-3-phosphate dehydrogenase activity and its mRNA. This enhanced expression of late markers was reflected in shortening the time period required for their first appearance as well as increasing their yield during the course of adipose conversion. By following the accumulation of glutamine synthetase mRNA serving as an early marker for adipose conversion, the synergistic effect of bezafibrate and dibutyryl-cAMP was already evident as early as 5 h following their addition to confluent 3T3-L1 cells. Hence, the induction of adipose conversion by bezafibrate in 3T3-L1 cells appears to involve an early event which is rate-limited by the availability of intracellular cAMP.
Subject(s)
Adipose Tissue/metabolism , Bezafibrate/pharmacology , Bucladesine/pharmacology , Cyclic AMP/metabolism , Adipose Tissue/drug effects , Adipose Tissue/enzymology , Animals , Cells, Cultured , Colforsin/pharmacology , DNA/analysis , Drug Synergism , Glutamate-Ammonia Ligase/genetics , Glutamate-Ammonia Ligase/metabolism , Glycerolphosphate Dehydrogenase/genetics , Glycerolphosphate Dehydrogenase/metabolism , RNA, Messenger/analysis , Rats , Rats, Inbred Strains , Theophylline/pharmacologyABSTRACT
Placentae from 21 days pregnant rats were assayed for long-chain fatty acid binding activity. Oleate binding activity, associated with a low-molecular-weight protein fraction resembling liver fatty acid binding protein (FABP or 'Z' protein), could be demonstrated after removal of serum albumin by fractionation of the placental cytosol on Sephadex G-75. The fatty acid binding activity in the placenta was 2 to 4 per cent of the FABP activity present in rat liver.
Subject(s)
Carrier Proteins/analysis , Cytosol/analysis , Neoplasm Proteins , Nerve Tissue Proteins , Placenta/analysis , Animals , Fatty Acid-Binding Protein 7 , Fatty Acid-Binding Proteins , Female , Liver/analysis , Molecular Weight , Oleic Acid , Oleic Acids/metabolism , Pregnancy , RatsABSTRACT
Transient exposure of cultured 3T3-L1 preadipocytes to hypolipidemic fibrate drugs results in extensive adipocyte conversion. Adipocyte conversion in culture was characterized by an increase in neutral lipids content and in adipocyte marker enzymes like hormone-sensitive lipase and glycerol-3-phosphate dehydrogenase. Adipocyte conversion in culture was also accompanied by induction of cyanide-insensitive peroxisomal palmitoyl-CoA oxidation. The conversion pattern exerted by fibrate drugs in 3T3-L1 cells was similar to that reported previously for primary cultured epididymal preadipocytes (R. Brandes, R. Arad and J. Bar-Tana, Biochim. Biophys. Acta, 877, 314-321 (1986)), and seems to refute clonal selection in the conversion sequel initiated by fibrate drugs in primary cultured preadipocytes.
Subject(s)
Adipose Tissue/drug effects , Bezafibrate/pharmacology , 1-Methyl-3-isobutylxanthine/pharmacology , Cells, Cultured , Dexamethasone/pharmacology , Microbodies/drug effects , Oxidation-ReductionABSTRACT
Cultured rat epididymal preadipocytes exposed for 24-72 h to either bezafibrate or clofibrate added to the culture medium were extensively converted to fat-loaded adipocytes. Adipocyte conversion increased during the first 5-7 days following plating, reaching a level of 100% and 60% conversion with bezafibrate and clofibrate, respectively, as compared to 10% conversion in their absence. Adipocyte conversion in culture was a saturable function of the hypolipidemic effectors and was associated with an increase in the incorporation rate of exogenous palmitate into triacylglycerols, in glycerol-3-phosphate dehydrogenase and hormone-sensitive lipase activities but not in lipoprotein lipase activity. Adipocyte conversion by hypolipidemic drugs was much more prominent than that exerted by dibutyryl cAMP, and the relative conversion efficiency of the two fibrate drugs did not correlate with their respective cAMP content of the culture. Hence, hypolipidemic drugs and dibutyryl cAMP appear to act independently in initiating adipose conversion in primary epididymal preadipocytes.
Subject(s)
Adipose Tissue/cytology , Hypolipidemic Agents/pharmacology , Adipose Tissue/drug effects , Adipose Tissue/enzymology , Animals , Bezafibrate/pharmacology , Bucladesine/pharmacology , Cell Differentiation/drug effects , Cells, Cultured , Clofibrate/pharmacology , Cyclic AMP/metabolism , Glycerolphosphate Dehydrogenase/metabolism , Lipase/metabolism , Lipoprotein Lipase/metabolism , Male , Rats , Triglycerides/metabolismABSTRACT
The effect of insulin on [3H]oleate binding to delipidated liver cytosolic proteins was studied in four groups of animals: untreated rats, streptozotocin induced diabetic rats, Psammomys obesus fed salt bush diet, and Psammomys obesus fed ordinary laboratory chow. The distribution of the protein bound [3H]oleate between low and high molecular weight cytosolic proteins in Psammomys differed from the distribution found in rats. Diet induced high insulin diabetes in Psammomys and streptozotocin induced low insulin diabetes in rats, modulated [3H]oleate binding in the same manner.
Subject(s)
Arvicolinae/metabolism , Carrier Proteins/metabolism , Diabetes Mellitus, Experimental/metabolism , Fatty Acids/metabolism , Liver/metabolism , Neoplasm Proteins , Nerve Tissue Proteins , Animals , Blood Glucose/analysis , Cytosol/metabolism , Fatty Acid-Binding Protein 7 , Fatty Acid-Binding Proteins , Fatty Acids, Nonesterified/metabolism , Insulin/blood , Rats , Rats, Inbred StrainsABSTRACT
The availability of medium-chain fatty acids as substrates for triacylglycerol synthesis was studied in cultured and suspended rat adipocytes and in pieces of human adipose tissue. Octanoate was virtually excluded from glycerol 3-phosphate esterification while serving as a substrate for diacylglycerol esterification. This specificity was similar to that of cultured rat hepatocytes.
Subject(s)
Adipose Tissue/metabolism , Fatty Acids/metabolism , Triglycerides/biosynthesis , Animals , Caprylates/metabolism , Glycerophosphates/metabolism , Humans , In Vitro Techniques , Male , Mathematics , Palmitic Acid , Palmitic Acids/metabolism , Rats , Substrate SpecificityABSTRACT
The binding of [1-(14)C]oleate to rat liver cytosol was studied, using gel filtration on Sephadex G-75 and G-50. In liver cytosols from control rats, most of the high-affinity oleate binding was in the region of 12 000-dalton proteins. In liver cytosols from diabetic and starved rats, a second peak of radioactivity appeared in the void volume. This peak was shown to be associated with a component having the molecular weight of 400 000. Evidence suggesting that a change in the composition of cytosolic binding proteins is involved is presented.
Subject(s)
Carrier Proteins/metabolism , Diabetes Mellitus, Experimental/metabolism , Liver/metabolism , Neoplasm Proteins , Nerve Tissue Proteins , Oleic Acids/metabolism , Animals , Carrier Proteins/isolation & purification , Cytosol/metabolism , Fatty Acid-Binding Protein 7 , Fatty Acid-Binding Proteins , Kinetics , Oleic Acid , Rats , StarvationSubject(s)
Acyl Coenzyme A/metabolism , Coenzyme A Ligases/metabolism , Liposomes/metabolism , Phosphatidylcholines/metabolism , Adenosine Triphosphate/metabolism , Animals , Biological Transport , Coenzyme A/metabolism , Microsomes, Liver/enzymology , Palmitic Acids/metabolism , Palmitoyl-CoA Hydrolase/pharmacology , RatsABSTRACT
PIP: The authors consider immigration policy in the particular setting of scale economies in consumption. A model of a jurisdiction with a collective good motive for instituting an immigration policy is developed, and comparative statistical results are derived^ieng
